its simple like how a bullet can have the same Momentum as someone throwing a brick.
P(momentum) = mass * velocity
a bullet will have a faster velocity but smaller mass
a brick has larger mass and lower velocity
in the end they can equal
u have to use a cushion that will slow down the car when it falls. Something that will slowly release air when pressed upon.
Its the same shit why stunt guys use foam mats to slow velocity.
in the end i would use a woopie cushion ( no joke )