Question

give reasons:
1. why sliding friction is slightly smaller than static friction?
2. why is it convenient to pull luggage bags fitted with rollers?

Answer 1

Dear Student

1. Friction comes into play when irregularities present in the surfaces of two objects in contact get interlocked with each other. In sliding, the time given for interlocking is very small. Hence, interlocking is not strong. Therefore, less force is required to overcome this interlocking. Because of this reason, sliding friction is less than static friction.

2. Rolling friction is less than sliding and static friction
Hence, by using rollers we are replacing sliding friction by rolling friction
So it is easier to pull the luggage.
Friction decreases as
Static friction>Sliding friction>Rolling friction

Regards