Answer:
2) Static friction is a force that keeps an object at rest .The term sliding friction refers to the resistance created by two objects sliding against each other . This can also be called kinetic friction . Sliding friction is intended to stop an object from moving
3) Friction is caused due to irregularities on the surfaces of objects in contact.If we carefully observe the surface of objects through magnifying lens we will see that there are tiny hills and grooves . When two surfaces come in contact with each other these hills and grooves interlock with one another and thus oppose motion .
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