Action vs. reaction
N3: Action = -reaction,
- To every action
- action = force on object 1 from object 2 = F1ɚ
- there is an equal and opposite reaction.
- reaction = force on object 2 from object 1 = F2ə
- i.e. F1ɚ = - F2ə
- demo with prof. and skateboard
- prof. pushes on skateboard toward E
- therefore skateboard pushes on prof. toward W
- forces equal in magnitude -- why does skateboard get accelerated to a much higher velocity?
- N2, acceleration inversely proportional to mass, mass of skateboard much less than prof.
- demo with prof. and floor of room instead of skateboard
- prof. moves, but room doesn’t, why?
- N2 again, mass of room much greater than prof.