# Relation between momentum and impact force

If we knew the momentum of a moving object, how would we calculate the force exerted by that object upon impact with a surface?

• If you know the rate of change in momentum, you can calculate the impact force Commented Oct 25, 2023 at 16:16
• @BobD Wouldn't the rate of change in momentum just highlight the difference in force between the initial and final points, as opposed to the force itself? Commented Oct 25, 2023 at 16:54
• You need a model of the force, as it depends on the details. The force will be a function of time. For instance, the dynamics and forces from a rubber ball and a billiard ball will be different. For a billiard ball you will have a larger force acting for a shorter time than for a rubber ball (smaller force acting along longer times), so that the total change in momentum is the same. Commented Oct 25, 2023 at 16:57
• @VV_721 Rate of change in momentum tells us the force , an external force is responsible for this rate of change in momentum of the object. momentum in initial and final points wouldn't be force itself only the change in momentum for a short time yields a force
– Razz
Commented Oct 25, 2023 at 17:08
• @Razz Oh okay, I see what you're saying. I think I misunderstood your previous comment. When you mentioned rate of change in momentum, I thought you implied that the velocity of the object was changing as it approached the surface, but now I realize that the change in momentum is caused by the impact with the surface, which is what you meant. Commented Oct 25, 2023 at 17:22