In physics, resistance force is the force which an effort force must overcome in order to do work on an object.

Resistance force is a component in the following equation,


where R equals resistance force, DR equals resistance distance, E equals effort force, and DE equals effort distance.

Resistance force is also a component in the following equation,

Work output = R DR

where R equals resistance force and DR equals resistance distance.

Resistance force, like most other forces, is measured in the U.S. customary unit, the pound, or the Metric unit, the newton.