Identify the correct statement from the following: A. Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket is negative. B. Work done by gravitational force in lifting a bucket out of a well by a rope tied to the bucket is negative. C. Work done by friction on a…

Question

Identify the correct statement from the following: A. Work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket is negative. B. Work done by gravitational force in lifting a bucket out of a well by a rope tied to the bucket is negative. C. Work done by friction on a body sliding down an inclined plane is positive. D. Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity is zero. E. Work done by the air resistance on an oscillating pendulum is negative. Choose the correct answer from the options given below:

Accepted Answer

(2) B and E only. A: the man's pull is upward and the bucket moves upward, so his work is positive. False. B: gravity acts down while the bucket moves up, so its work is negative. True. C: friction opposes the sliding, so its work is negative. False. D: the applied force acts along the motion, so its work is positive; it is the net work that is zero at uniform velocity. False. E: air resistance always opposes the bob's velocity, so its work is negative. True. B and E only.

Step-by-step solution

Why the other options are wrong