Frictional forces act in the direction opposite to the MOTION. That direction could be the same OR opposite to applied force.
-- If you push a loaded heavy wagon from behind, trying to get it going faster, friction is acting against you, opposite to your force.
-- If you push a loaded rolling heavy wagon from in front, trying to make it slow down, friction is acting with you, in the same direction as your force.
The acceleration of a body in a gravitational field is independent of its mass. Both the stones will fall with the same acceleration through the same height and hence they will strike the ground simultaneously. GIVE ME POINTS
