if momentum is conserved, that means that the total momentum in a system in a system before an interaction must be equal to the total momentum in a system
why do we need safety features in a car?
they increase the time taken for the same change in momentum, this decreases the rate of change of momentum, reducing resultant force, which reduces damage
what happens when a car stops?
if the car stops, so do the passengers. momentum is lost, so as force x time = change in momentum, when changing momentum in a short period of time, the force applied must be greater
force x time = change in velocity x change in mass
