Question

Friction in moving parts of a machine can be reduced by using ___________.

• A. lubricants
• B. ball bearings
• C. iron filings
• D. Both (A) and (B).

Answer 1

The correct option is D

Both (A) and (B).

Friction: It is defined as the force which opposes any tendency for relative motion between bodies in contact.

1. Lubricating reduces the friction in machine parts.
2. Ball bearing is used to reduce friction in rotation or slipping parts of machines.

So friction in moving parts of a machine can be reduced by using lubricants and ball bearings. Hence option D is correct.