Forces on a rotating man

Description

The model shows the orientation of forces on a man carrying a heavy box inside a rotating frame. 1. Force of gravity: It always act in vertically downward direction; 2. Contact force by the box; 3. Normal force: Acted by the frame's surface on to the person in vertically upward direction; 4. Friction: Now this is important, the man is rotating and we know that for any object to rotate there has to be a force called centripetal force acting towards the centre of rotation. This centripetal force in this case is provided by Friction. Hence we know the direction of friction.