1. Take a heavy attache case without wheels. Slide it on the ground.
2. Take another heavy attache case with wheels slide on the ground.
1. What difference do you feel in both the activities?
2. Why do you need to apply force in moving the heavy attache case with out wheel?
When we side an attache case without wheels on the ground, the ground exerts a greater amount of frictional force on the attche case. So we can say that a wheel reduces friction.
In the same manner the wheel of a cycle rotates on a rod like structure is called axel. Wheel and axel are simple machines.
1. We have to exert a large force to roll attache without wheel and a little force to roll attache with wheel.
2. When we slide an attache case without wheels on the ground, the ground exerts a greater amount of frictional force on the attache case.