Which one of these is NOT possible if friction did not exist on the earth?
ALighting a matchstick by striking it
BWriting with chalk on a board
CWalking on the ground
DFloating freely in zero-friction space
Answer & Solution
Correct answer: D. Floating freely in zero-friction space
Walking, writing with chalk, and lighting a matchstick all rely on friction (grip, scraping, heat from rubbing). Floating freely without friction is exactly what would happen in space; it isn't 'made impossible' by the absence of friction. So all everyday useful actions except the last one would fail without friction.
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