Question

Calculate the stopping distance of a car travelling with a speed of 72  Kmph and being accelerated with -5 m/sec2 .​

Answer 1

Vi = initial speed

v = Vi + a t

easy way to get time is use average speed during constant acceleration

Vaverage = Va = (13+0) /2 = 6.5 m/s

so time to stop = t = 26 / 6.5 = 4 seconds

so

0 = 13 + a (4)

a = -13/4 m/s^2