Physics - W.E.P. Question with Solution | TestHub
Match the following scenarios with the work done by the specified force.
List - I | List - II |
|---|---|
(P) Work done by gravitational force on a ball thrown upwards and returning to the thrower's hand. | (1) Positive |
(Q) Work done by friction on a block sliding on a rough horizontal surface over a distance . | (2) Negative |
(R) Work done by the normal force on a block sliding down an inclined plane. | (3) Zero |
(S) Work done by the tension force on a pendulum bob moving in a horizontal circle. | (4) Can be positive or negative |
Options:
Answer:
Solution:
For (P), the displacement is zero, so work done by gravity is zero. For (Q), friction always opposes motion, so work done by friction is negative. For (R), the normal force is always perpendicular to the displacement, so work done is zero. For (S), the tension force is always perpendicular to the instantaneous velocity (and thus displacement) in a horizontal circular motion, so work done is zero.
