question_answer

A truck and a car are moving with the same K.E. on a straight road. Their engines are simultaneously switched off. Which one will stop at a lesser distance?

Answer:

                The vehicle stops when its K.E. is spent in working against the force of friction between the tyres and the road. This force of friction varies directly with weight of the vehicle. As K.E. = work done = force of friction × distance. \[\therefore \]   \[\text{E}=\text{F}\times \text{s}\]    or            \[\text{s}=\frac{E}{F}\] For given K.E ; distance s will be smaller, where F is larger, such as in case of a truck. Therefore, the truck will stop at a lesser distance.