Question

A father and son pushed their car to bring it to the side of the road as it had stalled in the middle of the road. They experienced that although they had to push with all their might initially to move the car, the push required to keep the car rolling was smaller, once the car started rolling. Explain.

Answer 1

Initially, when they pushed the car static friction was acting and after it starts moving kinetic friction was acting since coefficient of kinetic friction is less than static friction hence they felt easier to push the car once it started moving

Answer 2

Because initially they had to apply force to set the car in motion but once the car started rolling, they had to apply force only to balance rolling friction of the car, the value of which is very less.