Question

4.
Give two examples where friction needs to be increased and two examples where friction needs to be
decreased​

Answer 1

Explanation:

A good example of this is a ball or wheel. They roll to help reduce friction. Another way to reduce friction is with a lubricant like grease or oil. Machines and engines use grease and oil to reduce friction and wear so they can last longer.

Examples of increasing friction-the tyres of a motor car and bicycles are made rough to increase the friction . when a ground or surface become slippery after rain or water splashing it is made rough by spreading sand to increase the friction.

Answer 2

Answer:

For example, treading of shoes and tires is done to increase friction. When friction is undesirable we have to reduce the friction. Friction can be minimized by using lubricants like oil and grease and by using ball bearing between machine parts.

Explanation:

hope it helps