An 1kg ball collides normally with a fixed vertical wall. Its incoming speed is 8 m/s and its speed after the collision is 4 m/s . Calculate the change in momentum of the particle. If the collision lasts 0.5 s calculate the impact force.

Consider two scenarios before and after. Before there is a velocity of 8m/s (with right being positive) and mass 1kg. after there is a mass of 1kg and a velocity of -4 m/s as right is positive and it bounces of the wall in the opposite direction. Now, we can find the total change in momentum (delta p) for before and after which will be momentum before - momentum after.momentum = massvelocity. Momentum before =18=8 Ns. Momentum after = 1*(-4)=-4 Ns. so, the total change in momentum is 8-(-4) = 12 Ns. Since the impulse of a force (F*t)= change in momentum (delta p). Then the impact force (F) = change in momentum/time. =12/0.5 = 24 Newtons.