1. Forces come in pairs Mrs. Trotter Vian Middle School Science
Newton’s Third Law
Forces come in pairs
Mrs. Trotter
Vian Middle School Science

2. For every action … there is a reaction that is equal in size but opposite in direction

4. ? confused? You can calculate and plot on a graph the velocity
direction
acceleration
? confused?

5. The diver pushes on the diving board and the diving board propels the diver into the air

6. You push your arms against the water… the water in the pool pushes back on you in the opposite direction

7. Rocket Motion The burning fuel produces a hot gas
The engine pushes the gas downward
The gas pushes the engine upward
When the force of the gas pushing upward becomes greater that the engine… the rocket blasts off!

8. So.. Newton’s 3rd Law
When you push on an object- we call this force the ACTION FORCE
the object will push back on you- we call this the REACTION FORCE

9. If the reaction force results in an unbalanced force…
The object will accelerate

10. Momentum a measure of how hard it is to stop a moving object
it’s the product of the objects mass & velocity
p=m x v

11. If a car and a slugbug are both moving at the same speed
If a car and a slugbug are both moving at the same speed.. Which will be harder to stop?
more mass

12. If two cars of equal mass move at different speeds… which is harder to stop?

13. The Law of Conservation of Momentum
the total momentum of a group of objects stays the same unless outside forces act on objects
collisions
friction
gravity

14. An object in motion will move in a straight line at a constant velocity until it encounters another force
Watch Mac