posted by xtian .
A man is dragging a trunk up the loading ramp of mover's truck. The ramp has a slope angle of 20 degree, and the man pulls upward with a force F whose direction makes an angle of 30 degree with ramp. a. How large a force F is a necessary or the component F, parallel to the ramp to be 80N? b. How large will the component F, then be?