WELCOME TO ISM PHYSICS!
THIS IS NOT OPTIONAL. YOU MUST CREATE AN ACCOUNT !
HOMEWORK SERVER. CHECK IT OUT!
Course: International School of MN, Eden Prairie MN, Mr. Ray Gonzales
Access Code Subscription Period: 3/20/19 - 6/30/19 Free Evaluation
Number of Students: This single access code can be used by 15 students
Physics LE Student Access Code: Internationalschool063019 (first letter is upper-case)
Once students are provided with the access code, they should go to www.PhysicsLE.com and click on "Physics LE for Students" for complete instructions on setting up their account.
Please set up your account. Your access code is FREE OF CHARGE.
WELCOME TO THE FUTURE!
Course: International School of MN, Eden Prairie MN, Mr. Ray Gonzales
Access Code Subscription Period: 3/20/19 - 6/30/19 Free Evaluation
Number of Students: This single access code can be used by 15 students
Physics LE Student Access Code: Internationalschool063019 (first letter is upper-case)
Once students are provided with the access code, they should go to www.PhysicsLE.com and click on "Physics LE for Students" for complete instructions on setting up their account.
Please set up your account. Your access code is FREE OF CHARGE.
WELCOME TO THE FUTURE!
How to enter an answer in scientific notation.
Please note: When entering an equation the program can be a little goofy.
So when you are multiplying variables you should put a * (star-thingy) between the variables.
Sometimes you can just type in an answer like 1/2mv^2 and it works fine.
The individuals who run this site are aware of this issue and are working on it.
But to be on the safe side, use the * symbol.
IF PHYSICS LE TELLS YOU YOUR ANSWER IS INCORRECT
AND YOU BELIEVE YOUR ANSWER IS CORRECT
TELL ME
So when you are multiplying variables you should put a * (star-thingy) between the variables.
Sometimes you can just type in an answer like 1/2mv^2 and it works fine.
The individuals who run this site are aware of this issue and are working on it.
But to be on the safe side, use the * symbol.
IF PHYSICS LE TELLS YOU YOUR ANSWER IS INCORRECT
AND YOU BELIEVE YOUR ANSWER IS CORRECT
TELL ME
Physics: The Mechanics of Nature
2018-2019 Mr. G The International School of Minnesota
Class location: always in room 309, the Physics Lab
Textbook: Giancoli 7th Edition
The purpose of this course, and of my teaching career, is to make you all confident in handling scientific subjects and solving problems. I want you to realize that regardless of your basic intelligence, you can do this. BUT IT TAKES HARD WORK!
I am going to show you, in the next 9 months, how almost everything in the universe works.
Learning physics – some advice
To succeed in this course you will need to learn the material at three different levels.
(i) You will need to learn the basic facts. You will be able to do some problems using just these basic facts, but even if you memorized every formula in the book this would only allow you to do a relatively small number of problems.
(ii) You will learn problem solving techniques or procedures. This is like learning to solve a puzzle or play a game. I will teach you techniques and strategies that work for many, many topics, but you have to practice.
(iii) You will learn to use your reasoning skills. If you approach Physics as reasoning based on a few basic facts and procedures, this course will be much easier than if you try to memorize how each problem is done. Furthermore, the underlying reasoning skills will be useful in any subsequent science and engineering course.
2018-2019 Mr. G The International School of Minnesota
Class location: always in room 309, the Physics Lab
Textbook: Giancoli 7th Edition
The purpose of this course, and of my teaching career, is to make you all confident in handling scientific subjects and solving problems. I want you to realize that regardless of your basic intelligence, you can do this. BUT IT TAKES HARD WORK!
I am going to show you, in the next 9 months, how almost everything in the universe works.
- Communication – Class content is what I present (slides and writing on the board), handouts, web posts,
and your text;
Class assignments and advice is on our class website (gonzmosis.com).
- Process – I will lead you point by point through the material, but unlike your courses in previous years, you will have to spend time on your own to read and learn some concepts from the text. We simply don’t have enough time to cover all of the details in class, plus, I am preparing you to study at a university.
- I will introduce material, show how it fits, and show example problem solutions in class
- You ask questions in class for clarity. Questions are good.
- We will practice problem solving every day in class. Bring your calculator.
- You will take notes on the material I present. Computers and tablets are fine.
- I will post the slides for each chapter, but only after we are done with that chapter.
- You will read the material after class for depth and to solidify your understanding.
- You will do problems as homework outside of class (plan for 45 min for each assignment)
- We will review problems in class on the day they are due
- SOMETIMES, the HW is on material we haven’t yet covered in class. This way, you get practice learning from the text.
- This website -- where you get details, updates, assignments, cool links, and cartoons
- gonzmosis.com is the place. Start the habit now of looking on Sunday evening.
- Homework – Problems will be assigned each week. Look on our website for updated details.
- I will review your HW to verify it is done
- We will review and solve many of them in class. If you get more than a few HW checks, you will be signed up for an additional HW lab.
- HW has the following important functions:
- It gives you practice in problem solving
- It shows you and me where you are having difficulty
- It provides a study guide for exams (The exams will be structured just like homework problems – if you do well on HW, you should do well on exams)
- Laboratory experiments – labs are for applying your learning and for practicing the scientific method
- Will be conducted in groups, can be analyzed in groups, but will be written individually
- Requires Prelab plan, in lab experiments, analysis, and lab report
- Lab score will be added to exam score for inclusion in your grade
- Physics Today -- what are the problems that physicists are working on now
- You will read chapters and articles or view videos to learn of current topics
- We will discuss these in class and relate them to what we’ve learned
- You will be amazed
- Your exams will cover this material
- Evaluation -- how do I measure your progress, and how do you demonstrate that you have learned physics
- Material we will cover this year: Chapters 1-9 and 11
- Your grade will be determined by the required periodic exam. HW and labs may also count as part of you final grade.
Learning physics – some advice
To succeed in this course you will need to learn the material at three different levels.
(i) You will need to learn the basic facts. You will be able to do some problems using just these basic facts, but even if you memorized every formula in the book this would only allow you to do a relatively small number of problems.
(ii) You will learn problem solving techniques or procedures. This is like learning to solve a puzzle or play a game. I will teach you techniques and strategies that work for many, many topics, but you have to practice.
(iii) You will learn to use your reasoning skills. If you approach Physics as reasoning based on a few basic facts and procedures, this course will be much easier than if you try to memorize how each problem is done. Furthermore, the underlying reasoning skills will be useful in any subsequent science and engineering course.
| 02_lectureoutline.pdf |
Week 1 August 27-31
Read Ch 1 and 2
Look at PDF lecture above
Tuesday: We will review units, sig dig, MKS, math and all that stuff.
Wednesday: We will start learning about kinematics in 1 D, derive some equations. Work some problems (together)
HW CH 2 problems 1-15 odd (Try to work these)_
Friday: learn about acceleration, work some problems, take a quiz.
Read Ch 1 and 2
Look at PDF lecture above
Tuesday: We will review units, sig dig, MKS, math and all that stuff.
Wednesday: We will start learning about kinematics in 1 D, derive some equations. Work some problems (together)
HW CH 2 problems 1-15 odd (Try to work these)_
Friday: learn about acceleration, work some problems, take a quiz.
| Click to Run |
WEEK 2
Tuesday: Derive one more equation. Work problems. Talk about free fall. READ about dropping things and throwing things in the air. It's all in CH 2.
For example. I throw a ball straight up and it returns to its initial position in 4 seconds.
a. What was its initial velocity?
b. How high did it go?
c. What was its final velocity?
Wednesday: Free fall problems.
Friday: A Lab! On free fall!
For example. I throw a ball straight up and it returns to its initial position in 4 seconds.
a. What was its initial velocity?
b. How high did it go?
c. What was its final velocity?
Wednesday: Free fall problems.
Friday: A Lab! On free fall!
| physics1sep4.pdf |
| phy1sep5.pdf |
ABOUT THE LAB
Ok. So just about every lab group got some crazy values for g.
From 5m/s/s to 7m/s/s. Hmmmmm. We all know the actual value is about 9.8m/s/s.
So clearly, there was some source of systematic error in your data.
And really, there are only two measurements made. Distance and time.
The distance you guys had right. I measured it myself and it is pretty close to 5 m.
So that leaves time. Most of the times I saw you collect were around 1.5 to 1.7 seconds.
I decided to do the lab myself. With stopwatch in one hand and ball in other I timed the fall of the ball.
I consistently got times of 1.01s, 0.99s, 1.03 s.
So my values for g came out to be about 10 m/s/s.
So my percent error was (9.8-10)/9.8 all times 100 = 2 percent! not bad.
So clearly, the problem was in the timing. Why do suppose my time measurements were more accurate than your's?
Think about it.
Ok. So just about every lab group got some crazy values for g.
From 5m/s/s to 7m/s/s. Hmmmmm. We all know the actual value is about 9.8m/s/s.
So clearly, there was some source of systematic error in your data.
And really, there are only two measurements made. Distance and time.
The distance you guys had right. I measured it myself and it is pretty close to 5 m.
So that leaves time. Most of the times I saw you collect were around 1.5 to 1.7 seconds.
I decided to do the lab myself. With stopwatch in one hand and ball in other I timed the fall of the ball.
I consistently got times of 1.01s, 0.99s, 1.03 s.
So my values for g came out to be about 10 m/s/s.
So my percent error was (9.8-10)/9.8 all times 100 = 2 percent! not bad.
So clearly, the problem was in the timing. Why do suppose my time measurements were more accurate than your's?
Think about it.
And try this quiz. Please note that some of the questions we have not covered yet. Just ignore those. Only questions about motion in a straight line.
WEEK 3:
Monday: Understanding motion graphs. Using Logger Pro.
Tuesday: Work problems involving objects thrown UP.
Wednesday: LAB: Using Logger pro with Little Blue and Little Red.
Friday: Work mixed problems from CH 2
Monday: Understanding motion graphs. Using Logger Pro.
Tuesday: Work problems involving objects thrown UP.
Wednesday: LAB: Using Logger pro with Little Blue and Little Red.
Friday: Work mixed problems from CH 2
Little Blue and Little Red
| phys1sep11.pdf |
WEEK 4:
Monday: Work free fall problems.
Tuesday: Motion graphs of free fall.
Wednesday: Free fall lab with logger pro
Monday: Work free fall problems.
Tuesday: Motion graphs of free fall.
Wednesday: Free fall lab with logger pro
| phys1sep14.pdf |
PRACTICE TEST BASIC EQUATIONS WILL BE PROVIDED
1. A car starting from rest, accelerates at 2m/s/s for 10 seconds.
a. What is the car's final velocity?
b. How far did the car travel?
a. Vf = Vo +at, Vo = 0m/s so Vf = at = 2m/s/s X 10 s = 20 m/s
b. deltaX = Vot + 1/2 a t ^2, again Vo = 0 m/s so delta X = 1/2 a t^2 = 1/2 (2m/s/s)(10s)^2 = 100m
2. A duck walking with a constant velocity of 1 m/s , walks 20m.
a. How long was the duck walking?
b. What was the duck's acceleration?
c. How does a duck know what direction south is? And how to tell his wife from all the other ducks?(click link below all this stuff)
a. V = X/t so t = X/V = 20m/1m/s = 20 s
b. since V is constant, acceleration = 0 m/s/s
3. A car with an initial velocity of 30m/s slows at a uniform rate to a stop in a distance of 100m.
a. What was the car's acceleration?
b. How long did the car take to stop?
a. Vo = 30m/s
Vf = 0m/s
delta X = 100 m
t= ?
so use Vf^2 - Vo^2 = 2ax, solve for a:
a = (Vf^2 - Vo^2)/2x = 0m/s - (30m/s)^2 /( 2 x 100m) = -4.5m/s/s
b. t = (Vf - Vo)/a = (0m/s - 30m/s)/-4.5m/s/s = 6.7 s
4. A puppy dog starting at rest, reaches a velocity of 10 m /s in 5 seconds.
a. What was the puppy dog's acceleration?
b. How far did the puppy dog travel?
c. What is the puppy dog's name?
a. a = (Vf - Vo)/t = (10m/s - 0m/s)/5s = 2m/s/s
b. x = Vot + 1/2 at^2 , Vo = 0m/s so x = 1/2(2m/s/s)x5^2 = 25 m
c. Sugar Bear
5. A BMW traveling with a constant velocity of 20m/s passes by a police car at rest.
At that moment, the police car accelerates at a constant rate of 2m/s/s.
a. How long will it take the police car to catch up to the BMW?
b. How FAR away do the two cars meet?
c. Who was driving the BMW?
a. For the BMW velocity is constant so x = vt so x = 20m/s x t
For the police Vo = 0m/s and a = 2m/s/s so x = 1/2at^2 so x = 1/2(2) x t^2 or x = t^2
x for BMW and x for police are equal sooooo
20t = t^2
20 = t or t = 20s
b. Then use the value for t in either equation for motion: BMW x = vt = 20m/s x 20 s = 400m
c. gonzo
6. You drop your physics book from the top of a 45m tall building.
a. How long does it take the book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
a. Choose an appropriate coordinate system. Down = positive would be good. Initial position of book = 0m is good.
So Vo = 0m/s. a = 10 m/s/s. and X = 45m
Use x=Vot + 1/2 at^2 and solve for t
Since Vo = 0m/s equation is X = 1/2 at^2
solving for t gives us
t = square root (2x/a) = sqrt( 2*45/10) = 3 s
b. Vf = Vo + at: Vf = 0 + 10m/s/s X 3s = 30 m/s
7. You throw your physics book straight up with a velocity of 10 m/s.
a. How high will the book go?
b. How long will it take the book to return to you?
c. What is the acceleration of the book at it's highest point?
For this problem, up is the positive direction and down in negative. So a = -g = about -10m/s/s.
Vo = 10m/s.
Since the book momentarily stops at the highest position we can say Vf = 0m/s.
Then use Vf^2 - Vo^2 = 2ax and solve for x
x = (Vf^2 - Vo^2)/2a = (0 - 10^2)/(2 x -10) = 5 m
b. To find time, realize that for the whole problem delta x = 0m (the book returns to its initial position)
use deltaX = Vot + 1/2at^2 and solve for t
0 = 10t +1/2(-10)t^2
5t^2 = 10t
5t = 10
t = 2 s
c. acceleration = about 10m/s/s the entire time.
8. Standing 30m above the ground, you throw your physics book straight down with a velocity of 5m/s.
a. How long will it take the poor book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
Since everything in this problem is DOWNWARD I would let down be the + direction.
So Delta X = 30m, Vo = 5m/s and a = g = about 10 m/s/s.
You could solve for t using a quadratic equation, but I would solve for Vf first.
Vf^2 = Vo^2 + 2ax. Vo = 0m/s, sooooo
Vf = sqrt(2ax) = sqrt(2*10m/s/s*30m) = 25 m/s (about)
Now solve for t.
t = (Vf - Vo)/a = (25m/s - 5m/s)/10m/s/s = 2s
9. From a position 20m above the ground, you toss a penguin straight up with a velocity of 10m/s.
a. How long till the penguin reaches the ground?
b. What is the velocity of the penguin as it reaches the ground?
c. How high above its initial position will the penguin travel?
For this problem I would let the initial position of the penguin =0m. Since the problem involves motion up and down, I will let up be positive and down be negative.
So Vo = 10m/s
delta x = -20m
a = g = -10 m/s/s
The easiest way to do this problem is to find Vf first.
Vf = +/- sqrt(Vo^2 + 2ax)
Vf = +/-sqrt(10m/s^2 + 2(-10m/s/s)(-20m)
since the penguin is moving down, Vf is negative
Vf = -sqrt(100 + 400) = -sqrt(500) = -22 m/s
Now find t using t =( Vf -Vo)/a = (-22m/s - 10m/s)/-10 = 3.2 s
To find how high the penguin goes use 2ax = Vf^2 - Vo^2 and solve for x. At the highest point Vf = 0m/s
x = (- (10m/s^2)/2(-10m/s/s) = 100/20 = 5m
There will be some questions about motion graphs.
1. A car starting from rest, accelerates at 2m/s/s for 10 seconds.
a. What is the car's final velocity?
b. How far did the car travel?
a. Vf = Vo +at, Vo = 0m/s so Vf = at = 2m/s/s X 10 s = 20 m/s
b. deltaX = Vot + 1/2 a t ^2, again Vo = 0 m/s so delta X = 1/2 a t^2 = 1/2 (2m/s/s)(10s)^2 = 100m
2. A duck walking with a constant velocity of 1 m/s , walks 20m.
a. How long was the duck walking?
b. What was the duck's acceleration?
c. How does a duck know what direction south is? And how to tell his wife from all the other ducks?(click link below all this stuff)
a. V = X/t so t = X/V = 20m/1m/s = 20 s
b. since V is constant, acceleration = 0 m/s/s
3. A car with an initial velocity of 30m/s slows at a uniform rate to a stop in a distance of 100m.
a. What was the car's acceleration?
b. How long did the car take to stop?
a. Vo = 30m/s
Vf = 0m/s
delta X = 100 m
t= ?
so use Vf^2 - Vo^2 = 2ax, solve for a:
a = (Vf^2 - Vo^2)/2x = 0m/s - (30m/s)^2 /( 2 x 100m) = -4.5m/s/s
b. t = (Vf - Vo)/a = (0m/s - 30m/s)/-4.5m/s/s = 6.7 s
4. A puppy dog starting at rest, reaches a velocity of 10 m /s in 5 seconds.
a. What was the puppy dog's acceleration?
b. How far did the puppy dog travel?
c. What is the puppy dog's name?
a. a = (Vf - Vo)/t = (10m/s - 0m/s)/5s = 2m/s/s
b. x = Vot + 1/2 at^2 , Vo = 0m/s so x = 1/2(2m/s/s)x5^2 = 25 m
c. Sugar Bear
5. A BMW traveling with a constant velocity of 20m/s passes by a police car at rest.
At that moment, the police car accelerates at a constant rate of 2m/s/s.
a. How long will it take the police car to catch up to the BMW?
b. How FAR away do the two cars meet?
c. Who was driving the BMW?
a. For the BMW velocity is constant so x = vt so x = 20m/s x t
For the police Vo = 0m/s and a = 2m/s/s so x = 1/2at^2 so x = 1/2(2) x t^2 or x = t^2
x for BMW and x for police are equal sooooo
20t = t^2
20 = t or t = 20s
b. Then use the value for t in either equation for motion: BMW x = vt = 20m/s x 20 s = 400m
c. gonzo
6. You drop your physics book from the top of a 45m tall building.
a. How long does it take the book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
a. Choose an appropriate coordinate system. Down = positive would be good. Initial position of book = 0m is good.
So Vo = 0m/s. a = 10 m/s/s. and X = 45m
Use x=Vot + 1/2 at^2 and solve for t
Since Vo = 0m/s equation is X = 1/2 at^2
solving for t gives us
t = square root (2x/a) = sqrt( 2*45/10) = 3 s
b. Vf = Vo + at: Vf = 0 + 10m/s/s X 3s = 30 m/s
7. You throw your physics book straight up with a velocity of 10 m/s.
a. How high will the book go?
b. How long will it take the book to return to you?
c. What is the acceleration of the book at it's highest point?
For this problem, up is the positive direction and down in negative. So a = -g = about -10m/s/s.
Vo = 10m/s.
Since the book momentarily stops at the highest position we can say Vf = 0m/s.
Then use Vf^2 - Vo^2 = 2ax and solve for x
x = (Vf^2 - Vo^2)/2a = (0 - 10^2)/(2 x -10) = 5 m
b. To find time, realize that for the whole problem delta x = 0m (the book returns to its initial position)
use deltaX = Vot + 1/2at^2 and solve for t
0 = 10t +1/2(-10)t^2
5t^2 = 10t
5t = 10
t = 2 s
c. acceleration = about 10m/s/s the entire time.
8. Standing 30m above the ground, you throw your physics book straight down with a velocity of 5m/s.
a. How long will it take the poor book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
Since everything in this problem is DOWNWARD I would let down be the + direction.
So Delta X = 30m, Vo = 5m/s and a = g = about 10 m/s/s.
You could solve for t using a quadratic equation, but I would solve for Vf first.
Vf^2 = Vo^2 + 2ax. Vo = 0m/s, sooooo
Vf = sqrt(2ax) = sqrt(2*10m/s/s*30m) = 25 m/s (about)
Now solve for t.
t = (Vf - Vo)/a = (25m/s - 5m/s)/10m/s/s = 2s
9. From a position 20m above the ground, you toss a penguin straight up with a velocity of 10m/s.
a. How long till the penguin reaches the ground?
b. What is the velocity of the penguin as it reaches the ground?
c. How high above its initial position will the penguin travel?
For this problem I would let the initial position of the penguin =0m. Since the problem involves motion up and down, I will let up be positive and down be negative.
So Vo = 10m/s
delta x = -20m
a = g = -10 m/s/s
The easiest way to do this problem is to find Vf first.
Vf = +/- sqrt(Vo^2 + 2ax)
Vf = +/-sqrt(10m/s^2 + 2(-10m/s/s)(-20m)
since the penguin is moving down, Vf is negative
Vf = -sqrt(100 + 400) = -sqrt(500) = -22 m/s
Now find t using t =( Vf -Vo)/a = (-22m/s - 10m/s)/-10 = 3.2 s
To find how high the penguin goes use 2ax = Vf^2 - Vo^2 and solve for x. At the highest point Vf = 0m/s
x = (- (10m/s^2)/2(-10m/s/s) = 100/20 = 5m
There will be some questions about motion graphs.
| physsep24.pdf |
WEEK OF OCTOBER 1
Start reading chapter 3 sections 1-4
MONDAY: define vector and methods of vector addition and subtraction
TUESDAY: work problems in class. HOMEWORK PAGE 68 1-6
WEDNESDAY: rectangular and polar representation of vectors. airplanes and boats. HW PAGE 71 44-47
FRIDAY: practice test. Show vector components using ALGADOO
READ THE CHAPTER SUMMARY BELOW
| 03_lectureoutline.pdf |
| phys1oct1.pdf |
WARNING! This video depicts men behaving stupidly.
WEEK OF OCTOBER 8 - 12
MONDAY: Practice adding vectors. Again.
TUESDAY : Using vectors to find EQUILIBRIUM
WEDNESDAY: FORCE TABLE LAB HW Page 69 9-14
THURSDAY: FORCE TABLE LAB
FRIDAY: FORCE TABLE LAB
MONDAY: Practice adding vectors. Again.
TUESDAY : Using vectors to find EQUILIBRIUM
WEDNESDAY: FORCE TABLE LAB HW Page 69 9-14
THURSDAY: FORCE TABLE LAB
FRIDAY: FORCE TABLE LAB
Try this VIRTUAL FORCE TABLE LAB
WEEK OF OCTOBER 15-19
MONDAY: More practice adding vectors!
TUESDAY: PRACTICE TEST on adding vectors.
WEDNESDAY: Review test, begin projectile motion.
MONDAY: More practice adding vectors!
TUESDAY: PRACTICE TEST on adding vectors.
WEDNESDAY: Review test, begin projectile motion.
| Click to Run |
WEEK OF OCTOBER 22-26
MONDAY: Equations for Projectile Motion, work problems. Insane video by Valdo.
TUESDAY: Work problems.
WEDNESDAY: LAB ON PROJECTILES!
FRIDAY: Work Problems.
WEEK OF OCTOBER 29 TO NOVEMBER 2
MONDAY: Lab on projectile motion. Really. I promise!
TUESDAY: Launching a projectile from an elevated position, like the top of a building.
WEDNESDAY: Practice test. Lab Due. Talk about lab.
FRIDAY: Review practice test.
WEEK OF NOVEMBER 5 TO NOVEMBER 9
MONDAY: PERIODIC 2 TERM 1
TUESDAY: Begin Newton's Laws.
WEDNESDAY: Work problems with F = ma.
FRIDAY: More problems with F = ma.
WATCH THESE VIDEOS!!!!!
MONDAY: PERIODIC 2 TERM 1
TUESDAY: Begin Newton's Laws.
WEDNESDAY: Work problems with F = ma.
FRIDAY: More problems with F = ma.
WATCH THESE VIDEOS!!!!!
NOVEMBER 26-30
MONDAY: Newton's Laws. Really. There are 3 of them. HW: Watch the videos above!
TUESDAY: The basics. Force, mass and acceleration.
WEDNESDAY: Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.
FRIDAY: Work problems. Lots of problems.
MONDAY: Newton's Laws. Really. There are 3 of them. HW: Watch the videos above!
TUESDAY: The basics. Force, mass and acceleration.
WEDNESDAY: Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.Free Body Diagrams.
FRIDAY: Work problems. Lots of problems.
WEEK OF DEC 3 TO DEC 7
MONDAY: Discuss, explain and work problems involving FRICTION.
TUESDAY: LAB Using logger pro and force sensors, determine a COEFFICIENT OF FRICTION.
WEDNESDAY: Review lab. Discuss, explain and work problems involving INCLINED PLANES.
FRIDAY: LAB DUE. Work problems involving inclined planes and TENSION.
MONDAY: Discuss, explain and work problems involving FRICTION.
TUESDAY: LAB Using logger pro and force sensors, determine a COEFFICIENT OF FRICTION.
WEDNESDAY: Review lab. Discuss, explain and work problems involving INCLINED PLANES.
FRIDAY: LAB DUE. Work problems involving inclined planes and TENSION.
WEEK OF DEC 10 TO DEC 14
MONDAY: Another way of determining a coefficient of friction.
TUESDAY: Friction lab due. Blocks and strings and pulleys.
WEDNESDAY: LAB Investigating Newton's Laws using blocks and strings and pulleys using motion detectors and logger pro.
FRIDAY: Review lab.
MONDAY: Another way of determining a coefficient of friction.
TUESDAY: Friction lab due. Blocks and strings and pulleys.
WEDNESDAY: LAB Investigating Newton's Laws using blocks and strings and pulleys using motion detectors and logger pro.
FRIDAY: Review lab.
Click on the book above to take a practice test.
We are currently in CHAPTER 4.
We are currently in CHAPTER 4.
WEEK OF DEC 17 TO DEC 21
MONDAY: HW due. Review HW.
TUESDAY: More problems with blocks and inclined planes. LAB FROM LAST WEEK DUE!
WEDNESDAY: LAB: Acceleration of a cart on an incline.
FRIDAY: Discuss/review lab results.
MONDAY: HW due. Review HW.
TUESDAY: More problems with blocks and inclined planes. LAB FROM LAST WEEK DUE!
WEDNESDAY: LAB: Acceleration of a cart on an incline.
FRIDAY: Discuss/review lab results.
PROBLEM:
Santa parks his/her sleigh on a snow covered roof top. The roof is angled at 10 degrees from the horizontal. The coefficient of static friction between the sleigh and snow is 0.1. (point 1) and a coefficient of kinetic friction of essentially zero. The mass of the sleigh is 2000 kg. Santa has a lot of toys. You can use 10m/s/s for g.
a) Will the sleigh slide down the roof or stay put?
b) If it does slide, what acceleration will it have?
Assume the sleigh starts to slide from rest with no friction. The distance from the initial position of the sleigh and the edge of the roof is 15 m. The edge of the roof is also 5 m above the ground.
c) What is the velocity of the sleigh when it reaches the edge of the roof?
d) How far from the house will the sleigh land?
Don't worry, the sleigh lands in snow so no toys are broken.
Then the ICE SHARKS show up.
Santa parks his/her sleigh on a snow covered roof top. The roof is angled at 10 degrees from the horizontal. The coefficient of static friction between the sleigh and snow is 0.1. (point 1) and a coefficient of kinetic friction of essentially zero. The mass of the sleigh is 2000 kg. Santa has a lot of toys. You can use 10m/s/s for g.
a) Will the sleigh slide down the roof or stay put?
b) If it does slide, what acceleration will it have?
Assume the sleigh starts to slide from rest with no friction. The distance from the initial position of the sleigh and the edge of the roof is 15 m. The edge of the roof is also 5 m above the ground.
c) What is the velocity of the sleigh when it reaches the edge of the roof?
d) How far from the house will the sleigh land?
Don't worry, the sleigh lands in snow so no toys are broken.
Then the ICE SHARKS show up.
It's OK. Santa stayed on the roof.
WEEK OF JAN 7 to JAN 11
MONDAY: I will be out of class. Work problems from CH4 on friction. You have a copy of that page. Turn in completed problems.
TUESDAY: We will review the friction problems.
WEDNESDAY: A lab?
FRIDAY: Practice test on friction, inclined planes, lions and tigers and bears. Oh my!
MONDAY: I will be out of class. Work problems from CH4 on friction. You have a copy of that page. Turn in completed problems.
TUESDAY: We will review the friction problems.
WEDNESDAY: A lab?
FRIDAY: Practice test on friction, inclined planes, lions and tigers and bears. Oh my!
The first person to turn in the correct answers to the practice test on Monday morning will get a crazy Japanese soda!
PRACTICE PERIODIC TEST
use 10m/s/s for g
1. A 1 Kg mass is suspended by a single string and is motionless. What is the tension in the string?
a. 0 N b. 1 N c. 10 N d. 100 N e. lavender
2. A 2 kg mass is suspended by a single string tied to the roof of an elevator. The elevator is moving up with a constant velocity.
What is the tension in the string?
a. less than 20 N
b. 20 N
c. greater than 20 N
d. impossible to tell without knowing the velocity of the elevator.
3. Now the elevator in problem 2 is accelerating up ward with a constant acceleration.
What is the tension in the string?
a. less than 20 N
b. 20 N
c. greater than 20 N
d. orange
4. Now the elevator in problem 2 is accelerating up ward with a constant acceleration of 1m/s/s.
What is the tension in the string?
a. 2 N b. 10 N c. 20 N d. 22 N e. blue
5. Now, the string in problem 4 breaks. What is the acceleration of the mass just after the string breaks?
a. 0 m/s/s. b. 2 m/s/s down c. 10 m/s/s down d. 22 m/s/s down
6. A 10 kg mass is on a frictionless level table. A string is attached to it and goes over a light pulley and is attached to an identical mass hanging from the side of the table.
What is the acceleration of the masses?
a. 0 m/s/s b. 5 m/s/s c. 10 m/s/s d. 100 m/s/s
7. In problem 6, what is the tension in the string?
a. 0 N b. 10 N c. 50 N d. 100 N
8. Two blocks are next to each other on a frictionless level surface. m1 is 1 kg and m2 is 2 kg. A force of 6 N acts horizontally on m1.
What is the acceleration of the blocks?
a. 0 m/s/s b. 2 m/s/s c. 3 m/s/s d. 6 m/s/s
a. 0 m/s/s b. 5 m/s/s c. 10 m/s/s d. 100 m/s/s
7. In problem 6, what is the tension in the string?
a. 0 N b. 10 N c. 50 N d. 100 N
8. Two blocks are next to each other on a frictionless level surface. m1 is 1 kg and m2 is 2 kg. A force of 6 N acts horizontally on m1.
What is the acceleration of the blocks?
a. 0 m/s/s b. 2 m/s/s c. 3 m/s/s d. 6 m/s/s
9. In problem 8, what force does m1 exert on m2?
a. 2 N b. 3 N c. 4 N d. 6 N
10. In problem 8, what magnitude force does m2 exert on m1? (magnitude just means absolute value)
a. 2 N b. 3 N c. 4 N d. 6 N e. yellow
11. A 15 kg basset hound is is resting on his bed. You need to move the bed to vacuum the floor, but the dog is too lazy to move The mass of the bed is negligible. The coefficient of kinetic friction between the bed and the floor is .5.
What horizontal force applied to the bed will cause the bed and dog to slide with constant velocity?
a. 15 N b. 50 N c. 75 N d. 150 N
a. 2 N b. 3 N c. 4 N d. 6 N
10. In problem 8, what magnitude force does m2 exert on m1? (magnitude just means absolute value)
a. 2 N b. 3 N c. 4 N d. 6 N e. yellow
11. A 15 kg basset hound is is resting on his bed. You need to move the bed to vacuum the floor, but the dog is too lazy to move The mass of the bed is negligible. The coefficient of kinetic friction between the bed and the floor is .5.
What horizontal force applied to the bed will cause the bed and dog to slide with constant velocity?
a. 15 N b. 50 N c. 75 N d. 150 N
12. A book on a level table has an initial velocity of 2 m/s. If the coefficient of kinetic friction between the book and table is .2 then how far will the book slide before it comes to rest?
a. 1m b. 2m c. 4m d. impossible to tell without knowing the mass of the book
13. A 1 kg mass and a 4 kg mass are connected to each other by a string running over a light pulley.
If the masses are released from rest, what will be the acceleration of the 1 kg mass?
a. 1 m/s/s b. 4m/s/s. c. 5 m/s/s d. 6m/s/s
a. 1m b. 2m c. 4m d. impossible to tell without knowing the mass of the book
13. A 1 kg mass and a 4 kg mass are connected to each other by a string running over a light pulley.
If the masses are released from rest, what will be the acceleration of the 1 kg mass?
a. 1 m/s/s b. 4m/s/s. c. 5 m/s/s d. 6m/s/s
14. In problem 13, what is the tension in the string after they are released?
a. 16 N b. 24 N c. 30 N d. 50 N
a. 16 N b. 24 N c. 30 N d. 50 N
15. A block with mass m is at rest on an inclined plane. The normal force acting on the block is...
a. less than mg b. equal to mg c. greater than mg d. could be greater than or less than mg, depending on the angle of the incline
16. A block is released from rest on a frictionless incline. What is the acceleration of the block? The angle of the incline is greater than 0 and less than 90
a. g b. gtan(theta) c. gsin(theta) d. gcos(theta)
17. A block is released from rest on an inclined plane and slides with constant velocity down the incline. Which of following statements is true?
a. the incline must be frictionless
b. the frictional force is equal to mgsin(theta)
c. the frictional force is equal to mgcos(theta)
d. the frictional force is equal to mgtan(theta)
18. A block is released from rest from the top of a 10m long frictionless incline having an angle of 30 degrees. What is the velocity of the block when it reaches the bottom of the incline?
a. 5 m/s b. 8.7 m/s c. 10 m/s d. 20 m/s
19. Now the block from problem 18 makes a smooth transition to the floor and slides 10 meters across the floor before coming to rest. What is the coefficient of friction between the block and floor?
a. .5 b. .87 c. 1 d. impossible to tell without knowing the mass of the block
20. A boy is sitting in the contraption shown below. The boy has mass m1 and the chair has mass m2. If they are not moving, what is the tension in the section of rope he is holding? You can ignore the mass of the scale.
a. m1g b. (m1+m2)g c. 2(m1+m2)g d. 1/2(m1+m2)g
WEEK OF JAN 14 TO JAN 18
Go over practice test and work more problems and take term 2 periodic 1.
Go over practice test and work more problems and take term 2 periodic 1.
WEEK OF JAN 22 TO JAN 25
BEGIN CHAPTER 5. THAT MEANS YOU SHOULD START READING CHAPTER 5. IN YOUR PHYSICS BOOK. THE ONE WITH THE MOUNTAIN ON IT.
READ SECTIONS 1, 2 AND 3.
ObjectivesAfter studying the material of this chapter, you should be able to:
1. Calculate the centripetal acceleration of a point mass in uniform circular motion given the radius of the circle and either the linear speed or the period of the motion.
2. Identify the force that is the cause of the centripetal acceleration and determine the direction of the acceleration vector.
3. Use Newton's laws of motion and the concept of centripetal acceleration to solve word problems.
4. Distinguish between centripetal acceleration and tangential acceleration.
5. State the relationship between the period of the motion and the frequency of rotation and express this relationship using a mathematical equation.
6. Write the equation for Newton's universal law of gravitation and explain the meaning of each symbol in the equation.
7. Determine the magnitude and direction of the gravitational field strength (g) at a distance r from a body of mass m.
8. Use Newton's second law of motion, the universal law of gravitation, and the concept of centripetal acceleration to solve problems involving the orbital motion of satellites.
9. Explain the "apparent" weightlessness of an astronaut in orbit.
10. State from memory Kepler's laws of planetary motion.
11. Use Kepler's third law to solve word problems involving planetary motion.
12. Use Newton's second law of motion, the universal law of gravitation, and the concept of centripetal acceleration to derive Kepler's third law.
13. Solve word problems related to Kepler's third law.
14. Identify the four forces that exist in nature.
TUESDAY JAN 22: WE WILL...
1. Review the last test
2. Learn the general properties of Uniform Circular Motion (UCM)
3. Calculate the centripetal acceleration of a point mass in uniform circular motion given the radius of the circle and either the linear speed or the period of the motion.
4. Identify the force that is the cause of the centripetal acceleration and determine the direction of the acceleration vector.
5. Use Newton's laws of motion and the concept of centripetal acceleration to solve word problems.
WEDNESDAY JAN 23: WE WILL...
1. Work lots of problems involving UCM and Newton's Law's. Work the 6 problems shown below. Be prepared to present your solution in class on Friday!
Specifically, problems involving...
Things tied to strings moving in horizontal or vertical circles.
Cars driving around curved roads.
Cars driving over hills.
Cars driving through dips in the road.
Fairground rides.
FRIDAY JAN 25: WE WILL...
1. Review HW. Work MORE problems involving UCM and Newton's Law's.
1) A 25 kg child is sitting 1.1 m from the center of a merry go round moves with a speed of 1.25 m/s.
a. Calculate the Centripetal Force needed to keep the child moving in a circle.
b. What types of force contributes to the total centripetal force keeping the child moving in a circle?
2) A 7000 kg Jet plane does a trick in which it turns in a horizontal circle. What
centripetal force does the air provide to the plane to keep it moving in a
circle if the plane is traveling with speed 525 m/s and is moving in a circle of
radius 6000 m.
3) A 2000 kg car turns in a loop of radius 15 m when entering a highway. The
car is traveling with speed 5 m/s around the loop.
a. Calculate the centripetal Force needed to keep the car in the turn?
d. What force keeps cars in a turn, if you do not have enough o f this force
what happens to the car?
4) A 4000 kg truck turns in a loop of radius 10 m when making a turn. Friction
can provide the truck a force of 19600 N but no greater. What maximum
speed can the truck make the turn with?
5) On a playground carousel sally, 30 kg, wants to see how fast she can go
before friction allows her to slip off. She knows that she can be provided a
maximum friction force of 88 N. She sits at the edge of the carousel, which is
1.2 m from the center. What maximum speed can she get
before she slips off?
6) A .1 kg ball on the end of a sting can be revolved in a horizontal circle. The
string is .5 m long and can hold a maximum tension of 130 N. What is the
maximum speed at which you can spin the object at the end of the string
without it snapping the string?
CLICK HERE FOR THIS WEEKS HOMEWORK. WORK PROBLEMS 1-6. THE ANSWERS ARE PROVIDED, BUT YOU MUST SHOW YOUR WORK! DUE ON TUESDAY MONDAY FEB 4.
WEEK OF 20 BELOW FREAKING ZERO JAN 28 TO FEB 1
MONDAY: Review online homework.
TUESDAY: Freeze. And work problems with banked roads and carnival rides that make you sick.
WEDNESDAY: Freeze. And work more problems on circular motion.
FRIDAY: Take a quiz on circular motion.
Try this racing simulation. Not as much fun as SUPER MARIO CART,
but it may help you understand centripetal forces.
CLICK HERE
but it may help you understand centripetal forces.
CLICK HERE
WEEK OF FEB 4 TO FEB 8
MONDAY: Turn in and discuss HOMEWORK. You know. The 6 problems I asked you to do over the weekend?
TUESDAY: Work MORE problems about carnival rides and CONICAL PENDULUMS.
WEDNESDAY: Work problems 7-15 from the same problem set as before.
FRIDAY: Take an itsy bitsy little practice test on circular motion.
MONDAY: Turn in and discuss HOMEWORK. You know. The 6 problems I asked you to do over the weekend?
TUESDAY: Work MORE problems about carnival rides and CONICAL PENDULUMS.
WEDNESDAY: Work problems 7-15 from the same problem set as before.
FRIDAY: Take an itsy bitsy little practice test on circular motion.
WEEK OF FEB 11-FEB 15
MONDAY: Review for Periodic 2.
TUESDAY: Review for Periodic 2.
WEDNESDAY: Take Periodic 2.
FRIDAY: Go over Periodic 2.
WEEK OF FEB 19 - 22
TUESDAY: BEGIN CH 6. Work: Motion, Force and ENERGY!
WEDNESDAY: The Work Energy Theorem. W = Delta K. What is work? What is kinetic energy?
FRIDAY: Problems. The ONLY way to learn this is to ...DO PROBLEMS!!!!!
CLICK HERE!!!!!
TERM 2 REVISION GUIDE
| physics_1_term_2_revision_2019.pdf |
WEEK OF MARCH 11 TO MARCH 15
MONDAY: REVIEW FINAL. START potential energy and conservation of energy. START WORKING PROBLEMS 12 TO 22. DUE FRIDAY. CLICK HERE!
TUESDAY: Work a bunch of problems involving conservation of energy.
WEDNESDAY: Work MORE problems involving conservation of energy.
FRIDAY: Lab on conservation of energy.
MONDAY: REVIEW FINAL. START potential energy and conservation of energy. START WORKING PROBLEMS 12 TO 22. DUE FRIDAY. CLICK HERE!
TUESDAY: Work a bunch of problems involving conservation of energy.
WEDNESDAY: Work MORE problems involving conservation of energy.
FRIDAY: Lab on conservation of energy.
If video does not play, try reloading page or click the icon on the upper right side of video to go to the SHOWME sight.
WEEK OF MARCH 18 - MARCH 22
MONDAY: Discuss area under f vs. X graphs and integrals. Review practice test.
TUESDAY: Introduce, discuss Hooke's Law and springs. Work problems with Hooke's Law.
WEDNESDAY: Lab: Determine force constant of a spring.
FRIDAY: Discuss lab results. Work more problems involving conservation of energy and springs.
That is a lot of Joules per second.
WEEK OF MARCH 25 TO MARCH 28
MONDAY: Discuss any issues with PHYSICS LE, begin MOMENTUM.
TUESDAY: Discuss, explain and define IMPUSE. Work related problems.
WEDNESDAY: Discuss explain and define CONSERVATION OF LINEAR MOMENTUM. Work problems.
MONDAY: Discuss any issues with PHYSICS LE, begin MOMENTUM.
TUESDAY: Discuss, explain and define IMPUSE. Work related problems.
WEDNESDAY: Discuss explain and define CONSERVATION OF LINEAR MOMENTUM. Work problems.
WEEK OF APRIL 8 TO APRIL 12
MONDAY: Watch tutorial video on momentum. Work on problem set from PHYSICS LE.
TUESDAY: Review momentum problems.
WEDNESDAY: LAB on CONSERVATION OF MOMENTUM.
FRIDAY: Finish lab and discuss results.
I am very pleased to see that a few more students have logged in and are attempting problems.
I know some of you may feel like this is a waste of time. I promise you it is not.
I also know, some of you are frustrated with the whole sig fig thing.
We have had this discussion. it is very simple. Make sure you answer has the SAME number of sig fig as the values in the problem.
Pretty much all of the problems have 3 sig fig.
So if you type in 31.23245356 as an answer....uhhh. Yeah. You will not receive full credit for the problem.
If you are not clear about the rules of sig fig I suggest you visit the the PHYSICS LE STUDENT GUIDE. Click here.
I know some of you may feel like this is a waste of time. I promise you it is not.
I also know, some of you are frustrated with the whole sig fig thing.
We have had this discussion. it is very simple. Make sure you answer has the SAME number of sig fig as the values in the problem.
Pretty much all of the problems have 3 sig fig.
So if you type in 31.23245356 as an answer....uhhh. Yeah. You will not receive full credit for the problem.
If you are not clear about the rules of sig fig I suggest you visit the the PHYSICS LE STUDENT GUIDE. Click here.
To view video full screen, click the icon on the upper right side of video. The blue white and green one. Not the share icon.
ALSO, for your entertainment I have asked the program to create subtitles. Neural nets and A.I.
Really? It's a nice feature and is amazing but sometimes it seems more like A.S. (Artificial Stupidity)
ALSO, for your entertainment I have asked the program to create subtitles. Neural nets and A.I.
Really? It's a nice feature and is amazing but sometimes it seems more like A.S. (Artificial Stupidity)
A certain someone has completed Momentum HW 1 and scored 100. That individual is now the designated Penguin/Prefect/Shadow Teacher for this class. If they want. Nice job!
MONDAY MORNING
If video does not play, try reloading page or click on icon on the upper right side of video.
Now work some problems!
Watch the video below for help with problems 10 and 11.
Watching the video is optional, of course. Doing the problems is not.
Watch the video below for help with problems 10 and 11.
Watching the video is optional, of course. Doing the problems is not.
Naturally, some of the requirements for submitting a correct answer remind me of a movie.
Specifically, your answers should have 3 sig fig. The video below illustrates the importance of the number 3.
Specifically, your answers should have 3 sig fig. The video below illustrates the importance of the number 3.
If you are paying attention you might notice that I made a rounding error. But my answer was accepted as correct.
So there is some flexibility in submitting numeric answers.
So there is some flexibility in submitting numeric answers.
I have extended the due dates on all the online hw assignments.
Your periodic will be about 20 free response questions very similar to the hw problems.
No penalties for minor sig fig errors.
If the video does not load or play click the icon on the upper right side of the image.
Sophia Q ROCKS! Nice work on doing the latest HW problems!
WEEK OF MAY 6 TO MAY 10
1. We will work problems involving torque.
2. We will learn about MOMENT OF INERTIA.
3. We will work problems involving moment of inertia.
Remember, if you have trouble loading or playing these videos, click the icon on the upper right side of window to go directly to my showme page.
CRANES! TORQUE IN ACTION!
IF A VIDEO DOES NOT LOAD TRY REFRESHING THE PAGE OR CLICK THE COLORED ICON ON THE TOP LEFT SIDE OF VIDEO
F.Y.I. There is someone SITTING on the right end of the see-saw. Forgot to draw them.
ISM PHYSICS 1 REVISION PACKET 2019
YOUR END OF TERM EXAM WILL BE ABOUT 60 MULTIPLE CHOICE QUESTIONS
YOUR END OF TERM EXAM WILL BE ABOUT 60 MULTIPLE CHOICE QUESTIONS
1. A car starting from rest, accelerates at 2m/s/s for 10 seconds.
a. What is the car's final velocity?
b. How far did the car travel?
a. Vf = Vo +at, Vo = 0m/s so Vf = at = 2m/s/s X 10 s = 20 m/s
b. deltaX = Vot + 1/2 a t ^2, again Vo = 0 m/s so delta X = 1/2 a t^2 = 1/2 (2m/s/s)(10s)^2 = 100m
2. A duck walking with a constant velocity of 1 m/s , walks 20m.
a. How long was the duck walking?
b. What was the duck's acceleration?
c. How does a duck know what direction south is? And how to tell his wife from all the other ducks?(click link below all this stuff)
a. V = X/t so t = X/V = 20m/1m/s = 20 s
b. since V is constant, acceleration = 0 m/s/s
3. A car with an initial velocity of 30m/s slows at a uniform rate to a stop in a distance of 100m.
a. What was the car's acceleration?
b. How long did the car take to stop?
a. Vo = 30m/s
Vf = 0m/s
delta X = 100 m
t= ?
so use Vf^2 - Vo^2 = 2ax, solve for a:
a = (Vf^2 - Vo^2)/2x = 0m/s - (30m/s)^2 /( 2 x 100m) = -4.5m/s/s
b. t = (Vf - Vo)/a = (0m/s - 30m/s)/-4.5m/s/s = 6.7 s
4. A puppy dog starting at rest, reaches a velocity of 10 m /s in 5 seconds.
a. What was the puppy dog's acceleration?
b. How far did the puppy dog travel?
c. What is the puppy dog's name?
a. a = (Vf - Vo)/t = (10m/s - 0m/s)/5s = 2m/s/s
b. x = Vot + 1/2 at^2 , Vo = 0m/s so x = 1/2(2m/s/s)x5^2 = 25 m
c. Sugar Bear
5. A BMW traveling with a constant velocity of 20m/s passes by a police car at rest.
At that moment, the police car accelerates at a constant rate of 2m/s/s.
a. How long will it take the police car to catch up to the BMW?
b. How FAR away do the two cars meet?
c. Who was driving the BMW?
a. For the BMW velocity is constant so x = vt so x = 20m/s x t
For the police Vo = 0m/s and a = 2m/s/s so x = 1/2at^2 so x = 1/2(2) x t^2 or x = t^2
x for BMW and x for police are equal sooooo
20t = t^2
20 = t or t = 20s
b. Then use the value for t in either equation for motion: BMW x = vt = 20m/s x 20 s = 400m
c. gonzo
6. You drop your physics book from the top of a 45m tall building.
a. How long does it take the book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
a. Choose an appropriate coordinate system. Down = positive would be good. Initial position of book = 0m is good.
So Vo = 0m/s. a = 10 m/s/s. and X = 45m
Use x=Vot + 1/2 at^2 and solve for t
Since Vo = 0m/s equation is X = 1/2 at^2
solving for t gives us
t = square root (2x/a) = sqrt( 2*45/10) = 3 s
b. Vf = Vo + at: Vf = 0 + 10m/s/s X 3s = 30 m/s
7. You throw your physics book straight up with a velocity of 10 m/s.
a. How high will the book go?
b. How long will it take the book to return to you?
c. What is the acceleration of the book at it's highest point?
For this problem, up is the positive direction and down in negative. So a = -g = about -10m/s/s.
Vo = 10m/s.
Since the book momentarily stops at the highest position we can say Vf = 0m/s.
Then use Vf^2 - Vo^2 = 2ax and solve for x
x = (Vf^2 - Vo^2)/2a = (0 - 10^2)/(2 x -10) = 5 m
b. To find time, realize that for the whole problem delta x = 0m (the book returns to its initial position)
use deltaX = Vot + 1/2at^2 and solve for t
0 = 10t +1/2(-10)t^2
5t^2 = 10t
5t = 10
t = 2 s
c. acceleration = about 10m/s/s the entire time.
8. Standing 30m above the ground, you throw your physics book straight down with a velocity of 5m/s.
a. How long will it take the poor book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
Since everything in this problem is DOWNWARD I would let down be the + direction.
So Delta X = 30m, Vo = 5m/s and a = g = about 10 m/s/s.
You could solve for t using a quadratic equation, but I would solve for Vf first.
Vf^2 = Vo^2 + 2ax. Vo = 0m/s, sooooo
Vf = sqrt(2ax) = sqrt(2*10m/s/s*30m) = 25 m/s (about)
Now solve for t.
t = (Vf - Vo)/a = (25m/s - 5m/s)/10m/s/s = 2s
9. From a position 20m above the ground, you toss a penguin straight up with a velocity of 10m/s.
a. How long till the penguin reaches the ground?
b. What is the velocity of the penguin as it reaches the ground?
c. How high above its initial position will the penguin travel?
For this problem I would let the initial position of the penguin =0m. Since the problem involves motion up and down, I will let up be positive and down be negative.
So Vo = 10m/s
delta x = -20m
a = g = -10 m/s/s
The easiest way to do this problem is to find Vf first.
Vf = +/- sqrt(Vo^2 + 2ax)
Vf = +/-sqrt(10m/s^2 + 2(-10m/s/s)(-20m)
since the penguin is moving down, Vf is negative
Vf = -sqrt(100 + 400) = -sqrt(500) = -22 m/s
Now find t using t =( Vf -Vo)/a = (-22m/s - 10m/s)/-10 = 3.2 s
To find how high the penguin goes use 2ax = Vf^2 - Vo^2 and solve for x. At the highest point Vf = 0m/s
x = (- (10m/s^2)/2(-10m/s/s) = 100/20 = 5m
a. What is the car's final velocity?
b. How far did the car travel?
a. Vf = Vo +at, Vo = 0m/s so Vf = at = 2m/s/s X 10 s = 20 m/s
b. deltaX = Vot + 1/2 a t ^2, again Vo = 0 m/s so delta X = 1/2 a t^2 = 1/2 (2m/s/s)(10s)^2 = 100m
2. A duck walking with a constant velocity of 1 m/s , walks 20m.
a. How long was the duck walking?
b. What was the duck's acceleration?
c. How does a duck know what direction south is? And how to tell his wife from all the other ducks?(click link below all this stuff)
a. V = X/t so t = X/V = 20m/1m/s = 20 s
b. since V is constant, acceleration = 0 m/s/s
3. A car with an initial velocity of 30m/s slows at a uniform rate to a stop in a distance of 100m.
a. What was the car's acceleration?
b. How long did the car take to stop?
a. Vo = 30m/s
Vf = 0m/s
delta X = 100 m
t= ?
so use Vf^2 - Vo^2 = 2ax, solve for a:
a = (Vf^2 - Vo^2)/2x = 0m/s - (30m/s)^2 /( 2 x 100m) = -4.5m/s/s
b. t = (Vf - Vo)/a = (0m/s - 30m/s)/-4.5m/s/s = 6.7 s
4. A puppy dog starting at rest, reaches a velocity of 10 m /s in 5 seconds.
a. What was the puppy dog's acceleration?
b. How far did the puppy dog travel?
c. What is the puppy dog's name?
a. a = (Vf - Vo)/t = (10m/s - 0m/s)/5s = 2m/s/s
b. x = Vot + 1/2 at^2 , Vo = 0m/s so x = 1/2(2m/s/s)x5^2 = 25 m
c. Sugar Bear
5. A BMW traveling with a constant velocity of 20m/s passes by a police car at rest.
At that moment, the police car accelerates at a constant rate of 2m/s/s.
a. How long will it take the police car to catch up to the BMW?
b. How FAR away do the two cars meet?
c. Who was driving the BMW?
a. For the BMW velocity is constant so x = vt so x = 20m/s x t
For the police Vo = 0m/s and a = 2m/s/s so x = 1/2at^2 so x = 1/2(2) x t^2 or x = t^2
x for BMW and x for police are equal sooooo
20t = t^2
20 = t or t = 20s
b. Then use the value for t in either equation for motion: BMW x = vt = 20m/s x 20 s = 400m
c. gonzo
6. You drop your physics book from the top of a 45m tall building.
a. How long does it take the book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
a. Choose an appropriate coordinate system. Down = positive would be good. Initial position of book = 0m is good.
So Vo = 0m/s. a = 10 m/s/s. and X = 45m
Use x=Vot + 1/2 at^2 and solve for t
Since Vo = 0m/s equation is X = 1/2 at^2
solving for t gives us
t = square root (2x/a) = sqrt( 2*45/10) = 3 s
b. Vf = Vo + at: Vf = 0 + 10m/s/s X 3s = 30 m/s
7. You throw your physics book straight up with a velocity of 10 m/s.
a. How high will the book go?
b. How long will it take the book to return to you?
c. What is the acceleration of the book at it's highest point?
For this problem, up is the positive direction and down in negative. So a = -g = about -10m/s/s.
Vo = 10m/s.
Since the book momentarily stops at the highest position we can say Vf = 0m/s.
Then use Vf^2 - Vo^2 = 2ax and solve for x
x = (Vf^2 - Vo^2)/2a = (0 - 10^2)/(2 x -10) = 5 m
b. To find time, realize that for the whole problem delta x = 0m (the book returns to its initial position)
use deltaX = Vot + 1/2at^2 and solve for t
0 = 10t +1/2(-10)t^2
5t^2 = 10t
5t = 10
t = 2 s
c. acceleration = about 10m/s/s the entire time.
8. Standing 30m above the ground, you throw your physics book straight down with a velocity of 5m/s.
a. How long will it take the poor book to reach the ground?
b. What is the velocity of the book as it strikes the ground?
Since everything in this problem is DOWNWARD I would let down be the + direction.
So Delta X = 30m, Vo = 5m/s and a = g = about 10 m/s/s.
You could solve for t using a quadratic equation, but I would solve for Vf first.
Vf^2 = Vo^2 + 2ax. Vo = 0m/s, sooooo
Vf = sqrt(2ax) = sqrt(2*10m/s/s*30m) = 25 m/s (about)
Now solve for t.
t = (Vf - Vo)/a = (25m/s - 5m/s)/10m/s/s = 2s
9. From a position 20m above the ground, you toss a penguin straight up with a velocity of 10m/s.
a. How long till the penguin reaches the ground?
b. What is the velocity of the penguin as it reaches the ground?
c. How high above its initial position will the penguin travel?
For this problem I would let the initial position of the penguin =0m. Since the problem involves motion up and down, I will let up be positive and down be negative.
So Vo = 10m/s
delta x = -20m
a = g = -10 m/s/s
The easiest way to do this problem is to find Vf first.
Vf = +/- sqrt(Vo^2 + 2ax)
Vf = +/-sqrt(10m/s^2 + 2(-10m/s/s)(-20m)
since the penguin is moving down, Vf is negative
Vf = -sqrt(100 + 400) = -sqrt(500) = -22 m/s
Now find t using t =( Vf -Vo)/a = (-22m/s - 10m/s)/-10 = 3.2 s
To find how high the penguin goes use 2ax = Vf^2 - Vo^2 and solve for x. At the highest point Vf = 0m/s
x = (- (10m/s^2)/2(-10m/s/s) = 100/20 = 5m
I am in the process of creating Physics LE question sets for your EOT revision packet.
I STRONGLY recommend that you start working on these problems
I STRONGLY recommend that you start working on these problems