Question

how friction can be reduced of increased?​

Answer 1

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⇒To reduce friction we can make the surfaces in contact smooth. Also adding a lubricant to two surfaces in contact reduces friction between them. Grease is added between the moving parts in machines, to reduce friction. Another method

Answer 2

To reduce friction we can make the surfaces in contact smooth. Also adding a lubricant to two surfaces in contact reduces friction between them. Grease is added between the moving parts in machines, to reduce friction. Another method of reducing friction is by using bearings. When ball bearings are introduced between two surfaces friction is reduced because of the freely rotating metal balls.

To increase friction, the surfaces in contact have to be made rough. The two surfaces in contact can also be pressed harder to increase force between them. Use of adhesive materials that stick surfaces , also increases friction between them