Question

A constant force of 5 Newton act for 5 seconds on a mass of 5 kilogram initially at rest. Calculate the final momentum

Answer 1

We can find the final momentum from the formula:

F∆t=m∆v=∆p,

F∆t=mv_f-mv_i=p_f-p_i,

here, F is the force that acts on the mass, m is the mass, ∆t is the time interval during which the force acts on the mass, ∆v=v_f-v_i is the change in velocity, v_i=0 is the initial velocity of the mass, v_f is the final velocity of the mass, ∆p=p_f-p_i is the change in momentum, p_i=0 is the initial momentum, p_f is the final momentum.

Then, we get:

F∆t=mv_f=p_f,

p_f=F∆t=5 N∙5 s=25 N∙s.