Question

If nothing is said about nature of friction then static friction and kinetic friction are

Answer 1

Explanation:

If two systems are in contact and moving relative to one another, then the friction between them is called kinetic friction. ... But when objects are stationary, static friction can act between them; the static friction is usually greater than the kinetic friction between the objects

Answer 2

Static friction is act on the body when the body is at rest whereas kinetic friction is act when the body is moving.

Explanation:

• Static friction is greater than kinetic friction {$\mu_s > \mu_k$}
• $\mu_s$ coefficient of Static friction and $\mu_k$ is coefficient of kinetic friction.
• Static friction is a maximum resisting force acting on the body that does not tend to move the body.
• Whereas Kinetic friction resists the relative movement of the ground when the body is not stationary.

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