Identify the correct statements 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 air resistance on an oscillating pendulum is negative. Choose the correct answer from the options given below:
Options

Question

Identify the correct statements 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 air resistance on an oscillating pendulum is negative. Choose the correct answer from the options given below:

Options

G1 Physics · Accepted Answer

The man's force and displacement are both upward, so A is false. Gravity acts downward while displacement is upward, so B is true. Friction opposes motion, so C is false. On a rough horizontal plane moving uniformly, the applied force balances friction but does positive work, so D is false. Air resistance opposes motion and does negative work, so E is true. Hence B and E only.