Q

The work done by friction is ______.

RRB Group D; RRB Group D 04/12/2018 / Shift-III; 27/11/2018 / Shift-III 2018
✓ Answer: C Always negative
The source selects C for a body sliding over a stationary rough surface, where friction opposes displacement. “Always” is too broad: friction can do positive or zero work in other situations.
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