Physics
posted by Amie on .
A person who is properly constrained by an overtheshoulder seat belt has a good chance of surviving a car collision if the deceleration does not exceed about 30 "'s".
Assuming uniform deceleration of this value, calculate the distance over which the front end of the car must be designed to collapse if a crash brings the car to rest from 85

vf^2=vi^2+2ad
for a,30*9.8 m/s^2; vf=0, vi= convert to m/s
solve for d 
A ball is tossed vertically upward from the ground and caught at a height of 15m. After 1.85seconds.
a)what is the velocity with which it was throuwn?
b)What maximum height does it reach.
c)whatt was the velocity when it was caught? 
A person who is properly constrained by an overtheshoulder seat belt has a good chance of surviving a car collision if the deceleration does not exceed about 30 "'s".
Assuming uniform deceleration of this value, calculate the distance over which the front end of the car must be designed to collapse if a crash brings the car to rest from 85.
can you please help me am stuck