Question

Brakes are applied to a train travelling at 72 km/h. After passing over 200m, its velocity is reduced to 36 km/h. Find the retardation in m/s-2

Answer 1

u = 72km/ hr= 20m/s

v=36km/hr= 10m/s

s = 200m

a=?

By using equation

v*2 - u*2=2as

10*2 - 20*2=2 a × 200

100-400=400a

-300/400= a

a= -3/4 ms*-2