Question

a moving train is brought to rest within 20 second by applying brakes. Find the initial velocity if he retardation due to brake is 2 meter per second

Answer 1

Hello !

Here's is the answer to your query ! 

Since the train is brought to rest , therefore we can conclude that:

v (final velocity) = 0 m/s

t (time taken) = 20 s

a (retardation) = - 2 m/s²

we need to find u (initial velocity)

Therefore, we know that v = u + at

Substituting the values we get :

0 m/s = u - 2 m/s² * 20 s

⇒ 40 m/s = u

Therefore the initial velocity was 40 m/s

Hope this helps!!!