Question

State the sign of work done by a force in the followinga. Work done by an applied force on a body moving on a rough horizontal plane with uniform velocityb. Work done by resistive force of air on a vibrating pendulum in bringing it to rest

Answer 1

Hey mate,

◆ Answers-
a) Positive
b) Negative

● Explaination-
a) Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity-
- Work done = Force × displacement
- Here, displacement is in same direction (both forward) as force, thus work done will be positive.

b) Work done by resistive force of air on a vibrating pendulum in bringing it to rest-
- Work done = Force × displacement
- Here, displacement is in opposite direction wrt force (forward and backward), thus work done will be negative.

Hope this helps you...

Answer 2

HLO MATE HERE U GO

⭐. The work done is positive because the applied force and displacement of the body are in the same direction.

⭐. The work done is negative because resistive force of air on a vibrating pendulum always acts in a direction opposite to the direction of motion of pendulum.