Question

a moving train is brought to rest with in 20 seconds by applying brakes find the initial velocity of the train if the retardation due to place is 2 metre per second square

Answer 1

using, v = u + at
As train finally stops v = 0
0 = u - 2*20
u = 40 m/s
So, initial velocity of train was 40 m/s

Answer 2

solution.

initial velocity, u=?

final velocity, v= 0m/s

Acceleration= -2m/s^2

so, a= v-u/ t

=> -2= 0 - u/20

=> -40= -u

=> u= 40m/s

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