The contact force acts on two surfaces contact when they are touching each other.
Answer: Option D
Explanation:
A contact force, the force exerted between two bodies in contact with each other. This force depends on the mass of the object. The more the mass of an object, the more the contact force exerted through it.
The contact force can either be continuous or impulsive. There are primarily three types of contact force- frictional, Applied and the Normal Force. Some basic and daily examples of contact force includes writing with a pen, a book placed on a shelf, hammering a nail, kicking a ball, etc.