Question

If Newton's second law of motion says that rate of change of momentum is directly proportional to the unbalanced force applied.

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How can we say that F is equal to (mv-mu)/t??

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where m=mass, v= final velocity, u=initial velocity, t=time and F=force applied

Answer 1

Newton's law of motion:

rate of change of momentum is directly proportional to the unbalanced force applied.

F = [ p_final - p_initial ]/t = [ mv - mu ]/t = m [ v- u ]/t

We know,

v = u + at

a = [ v - u ]/t

=> F = ma