Question

When two surfaces are coated with a lubricant, then they.
A.Stick to each other
B.Slide upon each other
C.Roll upon each other
D.None of these

Answer 1

Hint: Every molecule has a surface and when this surface is coated with a lubricant the two surfaces lose their property of friction. Due to the property of lubricants the two surfaces slide upon each other. Friction is the force that opposes or resists the motion when one molecule comes in contact with the other molecule.

Complete answer:
Lubricants are Substances that are used to reduce the frictional force between the two surfaces at mutual contact. When the surfaces move, heat will be generated. This heat can be reduced by applying the lubricants to the surface of the molecules or substances. Some of the examples of lubricants are oil or grease.
When grease or oil is applied to the two surfaces then these substances make the surfaces without friction and help these two surfaces to slide upon each other.
Heavy machine at the screw position will be applied with lubricants like oil or grease to avoid the tightening of screws and helps to reduce friction force.
This is due to the application of lubricant like oil or grease.
The correct answer is Option B.

Note:
There are three types of lubricants like oil based lubricants, water-based lubricants and silicone-based lubricants. This all-lubricant function is the same but the structure and properties are different. The lubricants must have a high boiling point, low freezing point, resistance to oxidation and have thermal stability.