Question

Whenever the surfaces in contact tend to move or move with respect to each other, the force of friction comes into play

• A. Only if the objects are solid
• B. only if one of the two objects is liquid
• C. Only if one of the two objects is gaseous
• D. Irrespective of whether the objects are solid, liquid or gas

Answer 1

The correct option is D

Irrespective of whether the objects are solid, liquid or gas

Friction:

1. Friction is a force that resists the relative motion between two surfaces that come into contact with each other. It is a force that opposes the relative motion of two bodies in contact.
2. Frictional force acts in a direction opposite to the direction of motion of the bodies in contact.Frictional force prevents the gliding of objects and ensures contact.
3. The kinetic energy during the motion is converted to thermal energy in friction.
4. Without frictional force one cannot imagine two surfaces be it solid,liquid or gas remaining in contact on the earth’s surface.

Therefore, option D is the correct choice.