a car with a dead battery is to be pushed along a straight road to give it a speed of 1m/s which is sufficient to start an engine? if one or two persons give a sudden push(unbalanced force) to it ,it hardly starts.but a continious push over some time can start the engine?why?

When two or more person give the car a sudden push they apply Force for very less time due to which it is not able to make car accelerates at speed of 1 metre per second but if one person apply Force for a long time its impact is more or it produces required acceleration of 1 metre per second square so it makes car move.