Resistance is the force that opposes the motion of an object. When a machine is used to move an object, the force of resistance must be overcome in order to move the object. The amount of force required to overcome the resistance depends on the weight of the object, the friction between the object and the surface it is moving on, and the angle of the incline.

Machines are able to overcome resistance by multiplying the force applied to the object. This is done by using levers, pulleys, gears, and other mechanical devices. By multiplying the force, machines are able to move objects that would be too heavy to move by hand.