Question

A bus running at a speed of 18 km/h is stopped in 2.5 seconds by applying brakes. Calculate the retardation produced.

Answer 1

18 km/hr = 18 * 5/18 = 5 m/s
By equation of motion v = u + at
Here, u=5 m/s , v=0 , t=2.5 s

so, 0 = 5 + 2.5 a
so, a = -5/2.5 = - 2 m/s²

Negative sign in acceleration means retardation. Therefore retardation produced is 2 m/s²