Question

An object retards uniformly at the rate of 4 m/s² for 5s and attains a velocity of 30 m/s. What was it's initial velocity?​

Answer 1

Given :-
• Final velocity = v = 30 m/s
• Retardation = a = - 4 m/s^2
• Time period = t = 5 s

To find :-
• Initial velocity = u

Using equation a = ( v - u ) / t
We get ,
( - 4 ) * ( 5 ) = 30 - u
So we get u = 50 m/s

Answer 2

I have attached hand written solution..