Two blocks of mass are sliding down an inclined plane (Fig. P4.79). (a) If the plane is...

Two blocks of mass are sliding down an inclined plane (Fig. P4.79). (a) If the plane is frictionless, what is the magnitude of the contact force between the two masses? (b) If the coefficient of kinetic friction between and the plane is and between and the plane is what is the contact force between the two masses? (c) If what is the contact force?