how wheel reduce friction the friction?
Hi Sushmita!
The friction caused by a wheel is rolling friction. Rolling friction is smaller than sliding friction. As the surface area coming into contact is reduced in case of a wheel, the friction is also reduced. Also, in the case of rolling an object over a surface, the contact surface changes continuously. As a result, irregularities of the two surfaces do not have enough time to get interlocked with each other. On the other hand, irregularities between the two surfaces have enough time to interlock with each other when the object slides over a surface. Hence, rolling friction is smaller than sliding friction. Therefore, it is easier to roll an object than slide it.
Cheers!!