Answer:
Impulse is defined as change in momentum of an object divided by time interval.
at t= 0s
initial velocity = u , initial momentum = mu
at some time t .
final velocity = V, final momentum= mv.
now, change in momentum= ( final - initial) = ( mv-mu)
time interval = (t-0) = t
impulse force = (mv-mu)/ ( t)
Ft = (mv-mu) proved .
this law is known as Newton's second law.