Download presentation

Presentation is loading. Please wait.

Published byArmando Stockton Modified over 4 years ago

1
Aim: What are Newtons 1 st and 3 rd Laws of Motion? Do Now: What is the weight of the box? m = 20 kg F g = mg F g = (20 kg)(9.8 m/s 2 ) F g = 196 N

2
So why isnt the box accelerating downward? No acceleration means no unbalanced forces In other words: Forces are balanced F Net = 0 The table is pushing up with an equal force This is called the Normal Force (F N ) F g = 196 N F N = 196 N

3
Normal Force Represented by F N Represented by F N Supporting force from the surface the object is on Supporting force from the surface the object is on Perpendicular and away from the surface Perpendicular and away from the surface If object is at rest in that direction, F N is equal to the objects weight If object is at rest in that direction, F N is equal to the objects weight FgFg FNFN

4
Newtons 1 st Law of Motion Law of Inertia If all the forces acting on an object are balanced (F Net = 0): a. an object at rest remains at rest Penny in beaker Demo

5
b. an object in motion will remain in motion with a constant velocity

6
Inertia – the ability of an object to resist a change in motion Objects at rest want to remain that way Objects in motion want to remain that way Inertia is dependent only on mass (the more mass, the more inertia)

7
A boy is pulling a 30 kg sled with a force of 100 N at a constant velocity Draw a free – body diagram to illustrate this F g = 294 N F N = 294 N F = 100 N Are we missing any forces? F F = 100 N Force of friction (F f ) – opposes the direction of motion Forces must be balanced

8
Object is at rest. What are the values of Forces A and B? 5 N 20 N Force A = Force B = 20 N 5 N

9
Newtons 3 rd Law – Law of Action – Reaction For every action there exists an equal but opposite reaction Demo – Balloon What is the action? What is the reaction?

10
Action – Jumper pushes on floor Reaction – floor pushes on jumper

11
Action – Foot pushes backward on floor Reaction – Floor pushes forward on foot

12
Action – Boat pushes person forward Reaction – Person pushes boat backwards

13
Action – Rocket pushes the air down Reaction – Air pushes the rocket up

Similar presentations

OK

How can we describe how objects move?. The law of BALANCED FORCES Objects at rest tend to stay at rest. Objects in motion tend to stay in motion.

How can we describe how objects move?. The law of BALANCED FORCES Objects at rest tend to stay at rest. Objects in motion tend to stay in motion.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To ensure the functioning of the site, we use **cookies**. We share information about your activities on the site with our partners and Google partners: social networks and companies engaged in advertising and web analytics. For more information, see the Privacy Policy and Google Privacy & Terms.
Your consent to our cookies if you continue to use this website.

Ads by Google

Ppt on the road not taken analysis Ppt on introduction to 3d coordinate geometry Ppt on cross docking definition Ppt on types of forests in india Ppt on higher education system in india Ppt on business model canvas Ppt on history of badminton and rules Ppt on history of internet free download Ppt on synchronous reluctance motor construction Ppt on world book day costumes