According to the iPod Physics website, the definition of “contact forces” is the type of force that results when two objects are in physical contact with each other. Some of the common examples of contact forces include applied forces, normal forces, tensional forces and frictional forces.
Contact forces require contact to accelerate an object. Another type of force that is similar to a contact force is applied force. An example of an applied force is a person pushing a chair across the floor. In this example, applied force is the force that has been exerted onto the chair by the individual pushing it.