Kinesiology 2241A/B Lecture Notes - Lecture 9: Ground Reaction Force, Pseudoephedrine, Slow Hand
Document Summary
If a force is applied to object, that object pushes back w/ same force. This pair of forces = action force + reaction force. Foot: applying action - therefore ball = accelerated but also fights back. Protests via reaction force (felt by toe) - equal + opposite but on 2 different bodies (foot and ball) Push against the ground & it will push back in a predictable way. We use this to accelerate + change speed. External forces: originate in external enviro + act on body. Internal forces: muscular contractions applying force to skeleton + causing limbs to move. Equal + opposite ground reaction force on hands - force applied by hands to ground. No enviro to push against = internal forces you will apply does nothing to move com b/c there is no reaction force to push off against. When you don"t have something to push against you cant accelerate com.