A block of mass is pulled up a smooth incline that makes an angle with the horizontal
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A block of mass m is pulled up a smooth incline that makes an angle α with the horizontal. The pulling force F acts horizontally (not along the incline) while the block moves a distance s up the plane.
(i) Resolve the horizontal force F into components parallel and perpendicular to the incline.
(ii) Derive an expression for the work done by the force F during the displacement s along the incline in terms of F, s and α.
(iii) Obtain the work done by gravity on the block for the same displacement.
(iv) Hence show that the net work done on the block equals Fscosα−mgssinα. If the block starts from rest, determine the speed it acquires after moving the distance s.