Per NCERT §5.3 + Points 2, work done by FRICTION (or viscous force) on a moving body is which?
ASame as KE
BZero
CNegative
DPositive
Answer & Solution
Correct answer: C. Negative
NCERT §5.3 + Points 2: friction opposes displacement ⇒ cos 180° = -1 ⇒ W < 0.
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