Question

A lorry and a car with the same kinetic energy are brought to rest by the application of brakes which provide equal retarding forces. Which of them will come to rest in a shorter distance?

• A. Lorry
• B. Car
• C. Both will stop at the same distance
• D. Car stops first but takes longer distance

Answer 1

The correct option is C Both will stop at the same distance

Work done by the brakes i.e force $\ast$ displacement transfers its kinetic energy i.e F $\ast$ d = $\frac{1}{2}$mv${}^2$

Since both the vehicles have the same kinetic energy and are subject to the same force(F) the distance covered by both lorry and car will be the same. Thus both will stop at the same distance.