In which of the following situations is friction not useful?
- Operation of a grinding machine
- Walking
- Application of brakes
-
Moving piston in a sleeve
The correct answer is: D
Explanation
friction, force that resists the sliding or rolling of one solid object over another.
Examples of friction in our daily life
- Driving of a a vehicle on a surface.
- Applying brakes to stop a moving vehicle.
- Skating.
- Walking on the road.