Enter the initial momentum, final momentum, and total time into the calculator to determine the drop force.

Drop Force Formula

The following equation is used to calculate the Drop Force.

Fd = (Mi-Mf) / t
  • Where Fd is the drop force (N)
  • Mi is the initial momentum (kg-m/s)
  • Mf is the final momentum (kg-m/s)
  • t is the change in time (s)

To calculate a drop force, subtract the final momentum from the initial momentum, then divide by the time.

It’s important to note that in the case of an object that bounces off a surface, the final momentum will be negative since it changed direction.

What is a Drop Force?


Drop force is a term primarily used in material testing where the impact force of a falling object on a target is measured.

At its core, drop force is a measurement of the impact that an object will experience as it falls onto a surface

How to Calculate Drop Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Drop Force.

First, determine the initial momentum. In this example, the initial momentum of a ball is 500 kg*m/s.

Next, determine the final momentum. After the ball bounces off a surface, the final momentum is -200 kg*m/s.

Next, determine the change in time. The change in time during the bounce is measured to be 5 seconds.

Finally, calculate the drop force using the formula above:

Fd = (Mi-Mf) / t

Fd = (500-(-200)) / 5

Fd = 140 N