The sign of work done by a force on a body is important to understand. State carefully if the following
quantities are positive or negative.
(i) Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket.
(ii) Work done by gravitational force in the above case.
(iii) Work done by friction on a body sliding down on inclined plane.
(iv) Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity.
(v) Work done by the resistive force of air on a vibrating pendulum in bringing it to rest,