Let an object of mass ‘m’ is moving along a straight line with initial velocity ‘u’. A constant force ‘F’ is applied in time ‘t’ to accelerate it and its final velocity becomes ‘v’.

Initial momentum, p₁ = mu
Final momentum, p₂ = mv
Change in momentum p₂ - p₁
mv – mu
m(v – u)
The rate of change of momentum =

Rate of change of momentum = force applied
Force
Force = k where k = proportionality constant

Force = kma where a = acceleration =