Momentum is a property of moving objects, which can be defined using the equation:
This equation shows three things:
1. An increase in mass leads to an increase in momentum.
2. An increase in velocity leads to an increase in momentum.
3. An object at rest (velocity = 0), will have no momentum.
The momentum of an object does not just depend on an object’s mass and speed. Velocity (speed in a given direction) is a vector quantity, so the momentum also depends on the object’s direction of travel.
As momentum depends on the object’s direction of travel, it can be a positive or negative value. If an object travelling in one direction has positive momentum, an object travelling in the opposite direction will have negative momentum.