a 10-kg block on a horizontal surface is pulled by a force with a magnitude of 20 n and direction pointing to 30 degrees above horizontal. the coefficient of kinetic friction between the block and the horizontal surface is 0.10. a) what is the magnitude of the normal force on the block? (2 pts) b) what is the magnitude of the kinetic frictional force on the block? (2 pts) c) what is the acceleration of the block? (2 pts)