The equation to calculate momentum is simple: P = M * V, where "P" stands for momentum, "M" stands for the mass of the object and "V" stands for the velocity of the object. So, the momentum of an object is the product of its mass and velocity. If an object is not moving, it has no momentum.

Weigh the object with a scale. Make sure you record the mass in term of kilograms. For example, suppose your object is a metal ball weighing 0.5 kilogram.

Roll or move the object over a distance. This is the only way anything can gain momentum. Time how long the object moves in seconds with your timer. For example, suppose your ball rolls down an incline in two seconds.

Record how far the object traveled in meters using a meter stick or ruler. In the example, you might measure that the object travels 1 meter.

Divide the distance by the time to calculate the velocity or speed of the object. In the example, the object travels 0.5 meter per second.

Calculate "P," or momentum, by multiplying your recorded velocity and mass together. Concluding the example, the metal ball has a momentum of 0.25 kilogram x meters/second.