A car is braked so that it slows down with uniform retardation from 15 m/s to 7 m/s while it travels a distance of 88 m. If the car continues to slow down at the same rate, after what further distance will it be brought to rest?

4 answers

d1 = 88 m.

V^2 = Vo^2 + 2a*d1.
a = (V^2-Vo^2)/2d1=(7^2-15^2)/176 = -1.0 m/s^2.

d2 = (V^2-Vo^2)/2a=(0-15^2)/-1.0 = 225 m

d = d2-d1 = 225 - 88 = 137 m.
in my book answer is 24.5
He travel at this speed far 4second. Brake are then apply and the body come to rest with uniform retardation in a further second graph of speed against time use the fine car acceleration
its wrong