For more information, please see full course syllabus of AP Physics 1 & 2

For more information, please see full course syllabus of AP Physics 1 & 2

## Discussion

## Study Guides

## Download Lecture Slides

## Table of Contents

## Transcription

## Related Books

## Share this knowledge with your friends!

## Copy & Paste this embed code into your website’s HTML

Please ensure that your website editor is in text mode when you paste the code.(In Wordpress, the mode button is on the top right corner.)

- - Allow users to view the embedded video in full-size.

*Since this lesson is not free, only the preview will appear on your website.*

### Related Articles:

### Newton's 3rd Law

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

- Intro 0:00
- Question 1 0:17
- Question 2 0:44
- Question 3 1:14
- Question 4 1:51
- Question 5 2:11
- Question 6 2:29
- Question 7 2:53

### AP Physics 1 & 2 Exam Online Course

### Transcription: Newton's 3rd Law

*Hi everyone and welcome back to Educator.com.*0000

*I am Dan Fullerton and today we are going to continue our mini-lessons as we do the first page of the APlusPhysics worksheet on Newton's Third Law.*0003

*Take a minute and download that from the link below and see if you can do it and then let us check our answers together.*0010

*Number 1 -- A student pulls a 60 N sled with a force having a magnitude of 20 N.*0017

*What is the magnitude of the force that the sled exerts on the student?*0022

*If the student pulls with a force of 20 N, then the sled must exert that force back on the student by Newton's Third Law.*0026

*The 60 N sled is just referring to the weight of the sled, so this one is all about reading the question.*0036

*Number 2 -- If we have a 65 kg astronaut and the astronaut exerts a force with a magnitude of 50 N on a satellite, that she is repairing, the magnitude of the force that the satellite exerts on her is...?*0045

*Well, it has to be the exact same according to Newton's Third Law -- the force of object 1 on 2 is equal in magnitude and opposite in direction to the force of 2 on 1.*0058

*Number 3 -- A 400 N girl -- so that is the weight of the girl -- standing on a dock exerts a force of 100 N -- so the girl is exerting a force of 100 N on a 10,000 N sailboat and that is the weight of the sailboat.*0072

*As she pushes it away from the dock, how much force does the sailboat exert on the girl?*0087

*Well that is going to be equal and opposite to the force that the girl exerts on the sailboat.*0092

*That is 100 N, so this also must be 100 N.*0098

*Do not let the weight of the girl or the weight of the sailboat throw you off. It is all about reading these questions carefully.*0103

*Number 4 -- A carpenter hits a nail with a hammer.*0111

*Compared to magnitude of the force the hammer exerts on the nail, the magnitude of the force the nail exerts on the hammer during contact is...?*0114

*It must be the exact same -- again Newton's Third Law -- forces come in pairs with the same magnitude, but opposite in direction.*0121

*Number 5 -- A woman is pushing a baby stroller. Compared to the magnitude of the force exerted on the stroller by the woman, the magnitude of the force exerted on the woman by the stroller is...?*0132

*Again, the exact same thing and hopefully we are catching a pattern here -- the same Newton's Third Law.*0142

*Number 6 -- When a child squeezes the nozzle of a garden hose, water shoots out of the hose toward the east, so if water is shooting out toward the east, what is the direction of the force being exerted on the child by the nozzle?*0150

*Again, according to Newton's Third Law, if the water is shooting out towards the east, the force must be to the opposite side or the west.*0162

*Last question -- A 100 kg boy and a 50 kg girl each holding a spring scale pull against each other as shown right here.*0175

*The graph below shows the relationship between the magnitude of the force that the boy applies on a spring scale in time.*0182

*If you notice it goes from 0 to about 12 N, linearly, over 3 seconds and the question we are being asked now is which graph best represents the relationship between the magnitude of the force that the girl applies on her spring scale in time?*0188

*Again, they have to be the exact same, but opposite in direction by Newton's Third Law, so the graph that goes from 0 - 12 N linearly is this one, Number 1.*0205

*That concludes page 1 of the Newton's Third Law worksheet.*0218

*Thanks so much for your time everyone and make it a great day!*0222

## Start Learning Now

Our free lessons will get you started (Adobe Flash

Sign up for Educator.com^{®}required).Get immediate access to our entire library.

## Membership Overview

Unlimited access to our entire library of courses.Learn at your own pace... anytime, anywhere!