Work Energy And Power Question 3
Question: Assertion : Work done by friction on a body sliding down an inclined plane is positive. Reason : Work done is greater than zero, if angle between force and displacement is acute or both are in same direction.
Options:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: E
Solution:
When a body slides down on inclined plane, work done by friction is negative because it opposes the motion (q = 180° between force and displacement)
If $ \theta <90{}^\circ $
then $ W $ =positive because $ W=F.s.\cos \theta $
