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

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

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

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

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

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!

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

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

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

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

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

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

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