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 :
(a) work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket .
(b) work done by gravitational force in the above case ,
(c ) work done by friction on a body siding down an inclined plane ,
(d ) workdone by an applied force on a body moving on a rough horizontal plane woth uniform velocity .
(d) work done by the resistive force of air on a vibrating pendulum in bringing it to rest .

Explanation

Positive