The contact force applied by a body A on another body B is equal to the normal force between the two bodies. From this, it can be concluded that

Step-by-step solution

The contact force F_ c between two bodies is the resultant of the normal force N and the frictional force f . F_ c = N^2 + f^2 Given that the contact force is equal to the normal force, we have F_ c = N . N^2 + f^2 = N N^2 + f^2 = N^2 f = 0 Thus, the frictional force between the bodies is zero. The frictional force can be zero if the surfaces are frictionless, or if the surfaces are rough but there is no tendency of relative motion between them. If the surfaces are rough and the frictional force is zero, the bodies