A man in a train station is towing his 20kg trunk by pulling on a strap at an angle θ above the horizontal. He pulls on the strap with a 35N force and the force of friction by the surface on the trunk is 20N. As a result, the trunk is moving at a constant speed.
(a) Draw a free body diagram.
(b) What angle does the strap make with the horizontal?
(c) What is the normal force exerted by the ground on the trunk?