Question

NTSE physics question Of the following statements choose the correct combination. a. .Grease is used to reduce friction in a bicycle chain. b. Ball bearings are used to reduce .friction in a fan. c. Oil can be used to increase friction in car engine. d. Talc can be used to reduce friction when an object is sliding on a surface. 1. a, b, d 2. a, c, d 3. b, c, d 4. a, b, c Please explain! Thanks

Answer 1

1.  a, ,b, d

Grease, oil, talcum powder , ball bearings all can be used to reduce friction.

These materials are soft, viscous, allow sliding of surfaces on them easily.  They form thin layers between sliding surfaces.

oil does not increase friction.