Question

Is there a force of friction between the wheels of a moving train and iron rails? If yes, name the type of friction. If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?

Answer 1

Rolling friction:

1. When a wheel, ball, or cylinder rolls freely above a surface, as in ball and roller bearings, rolling friction occurs.
2. The distribution of energy involved in the twisting of the items appears to be the main cause of friction in rolling.
3. The ball is considerably packed down and the level surface is somewhat indented in the contact zones when a hardball is rolling on a level surface.
4. The obstruction to motion caused by the elastic bend or compression created at the leading section of the part in contact is not entirely compensated as the substances spring back to their original shape at the trailing section.

Conclusion:

1. Yes, the rolling force works between the wheels and iron nails. The force resisting the motion of a rolling body on a surface is known as rolling friction or rolling resistance.
2. The rolling of a ball or wheel on the ground is an example of Rolling friction. The friction between these will decrease if a cushion will be introduced between them.

Hence, a rolling force exists between the wheels of a moving train and the iron rails. Friction is reduced when an air cushion is placed between the wheel and the rails.