A body of mass 40kg is accelerating at a
rate of 9m/s² . What is the rate of change of linear momentum?

Momentum = (mass) x (speed)Mass is constant, so the rate of change of momentum is                        (mass) x (rate of change of speed) .But (rate of change of speed ) is just acceleration.So the rate of change of momentum is (mass) x (acceleration).But (mass) x (acceleration) is Force.So Force is the rate of change of momentum.    Verrrrrrrry interesting ! In this problem, Force = (40 kg) x (9 m/s²) = 360 newtons.One 'Newton' is one kilogram-meter per second² .Unit of momentum is (kilogram)-(meter per second), so 'newton'is also a unit of time rate of change of momentum.Rate of change of momentum is 360 momentum units per second.

Momentum = mass * velocity :  p = mvTime Rate of change of linear momentum of an object    Δp / Δt           = Δ (m v ) / Δt  = m Δv / Δt  = m a          =  Force acting on the object         =  40 Kg * 9 m /sec² = 360 Newtons==================================================Δ denotes change in a quantity.  Δp = p2 - p1           Δt =  t2 - t1p2  =  momentum at time t2  and          p1 = momentum at time t1v2 = velocity at time t2              v1 = velocity at time t1a = acceleration, constant and  same at t1 and t2let u = velocity at time t = 0Time rate of change of moment um is actually =  (p2 - p1) / (t2 - t1)p2 = m v2            p1 = m v1        So  p2 - p1 = Δp  = m (v2 - v1)v2 = u + a t2          v1 = u + a t1        so,  v2 - v1 = Δv = a (t2 - t1 )    = a  ΔtSo  p2 - p1 = m (v2 - v1 )  = m a ( t2 - t1)So            ( p2 - p1 )  / (t2 - t1 )  =  Δp / Δt  = m a  = 40 * 9 = 360 Newtons