Physics
State whether work is done or not by writing yes or no, in the following cases?
(a) A man pushes a wall.
(b) A coolie stands with a box on his head for 15 min.
(c) A boy climbs up 20 stairs.
Related Questions
A force F acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of force.
(a) Write the expression for the work done by the force.
(b) What should be the angle between force and displacement so that the work done is (i) zero, (ii) maximum?
A body is moved in a direction opposite to the direction of force acting on it. State whether the work is done by the force or work is done against the force.
Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
A boy of mass m climbs up a stairs of vertical height h.
(a) What is the work done by the boy against the force of gravity?
(b) What would have been the work done if he uses a lift in climbing the same vertical height?