Question

friction.both desirable and undesirable in.engineering application​

Answer 1

Desirable Examples:

i) Friction between the tire and breaks is helpful in slowing down the vehicles

ii) Windage Friction in the series motor helps in protecting it when it is driven without load due to some mistake

Undesirable examples:

i) Due to the frictional and windage losses, motor has to provide more toque and power than required by the load

ii) Friction causes wear in mechanical bearings and thus, bearings need to be replaced after a certain period