PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy
Problem
Two identical trolleys A and B, each of mass m, are on a friction-less horizontal track. Trolley A carries an extra sandbag of mass m, whereas trolley B carries none. Both trolleys are simultaneously given a horizontal push so that they start moving with the same speed u.
Read the following statements and answer the questions that follow.
(i) State, with reason, which trolley possesses greater kinetic energy immediately after the push.
(ii) A student argues that, because the trolleys were given the same push, their kinetic energies must be equal. Explain the conceptual error in this argument.
(iii) Suppose the sandbag is now transferred from trolley A to trolley B while both are still moving at speed u. Qualitatively compare the new kinetic energies of the two trolleys with their original values and justify your answer.