Question

On applying brakes a moving train comes to rest within 20 seconds. Find the initial velocity if the retardation due to brakes applied is 4m/s².​

Answer 1

Explanation:

u = ?

v = 0

t = 20 second

Retardation = - 4m/s²

using first equation of motion

v u+at

0 = u + ( -4×20)

0 = u -80

u = 80 m/s

initial velocity of train = 80 m/s