hi, i'm wondering if anyone could explain to me why one uses the following technique to solve this problem. Let's say we've a 10 kg object. The force exerted on it is F = 10 + 2t The force acts on it for two (2) seconds. If it starts at rest, what is the final velocity? I used this technique to solve the problem, after first making a mistake dp = F(net) * dt breaking that down to dp = (10 + 2t) * dt integration giving 10t + t^2 from 0 to 2 giving 24 kg * m/s so dp = 24 kg * m/s m(v(2)-v(1)) = 24 kg * m/s 10 kg (v(2)-0) = 24 kg * m/s v(2) = 2.4 m/s this is the correct answer, however, initially i tried m(v(2)-v(1)) = (10 + 2t) * dt 10 kg (v(2)-0) = 14N * 2s resulting in a velocity of 2.8 m/s why do i use integration before involving momentum is my question. thanks for anyone who might be able to help!