Action and reaction forces are _____. They produce _________accelerations in the two bodies, if the mass of the bodies are equal.
The contact force exerted by a body A on another body B is equal to the normal force between the bodies. We conclude that(a) the surface must be frictionless(b) the force of friction between the bodies is zero(c) the magnitude of normal force equal that of friction(d) the bodies may be rough but they don't slip on each other.