Question

according to recent typical test data, a Ford Focus travels 0.23 mi in 19 seconds, starting from rest. The same car, when braking from 59.0mph on dry pavement, stops in 141 ft. Assume constant acceleration in each part of its motion, but not necessarily the same acceleration when slowing down as when speeding up. Find the magnitude of this car's acceleration when braking.

Answer 1

first find the terminal velocity
distance=1/2 a t^2 solve for a
then, vf= at

Then solve for the braking acceleration
0= vabove*2 +2ad solve for a