Identify the correct statements: (A) Work by a man lifting a bucket from a well is negative. (B) Work by gravity while lifting the bucket is negative. (C) Work by friction on a body sliding down an incline is positive. (D) Work by an applied force on a body moving at uniform velocity on a rough horizontal plane is zero. (E) Work by air resistance on an oscillating pendulum is negative. Choose the correct combination.
Options

Question

Identify the correct statements: (A) Work by a man lifting a bucket from a well is negative. (B) Work by gravity while lifting the bucket is negative. (C) Work by friction on a body sliding down an incline is positive. (D) Work by an applied force on a body moving at uniform velocity on a rough horizontal plane is zero. (E) Work by air resistance on an oscillating pendulum is negative. Choose the correct combination.

Options

G1 Physics · Accepted Answer

Gravity does negative work while lifting, so B is true. Air resistance always opposes the pendulum's motion and therefore does negative work, so E is true. A, C and D are false. Hence option A (B and E only).