A 5000-kg freight car having a kinetic energy of 2500 J and going at a speed of 1 m/s crashes into an approaching train on the same track that is moving at a speed of 2 m/s with a kinetic energy of 10,000 J. When they collide and couple together. the amount heat energy they produce is

Question

Quizplus · Accepted Answer

The total initial kinetic energy of the system is the sum of the kinetic energies of both the freight car and the approaching train, which is 2500 J + 10,000 J = 12,500 J. When they collide and couple together, the principle of conservation of energy states that the total energy of the system is conserved, but the kinetic energy can be converted into other forms of energy, such as heat. Since there's no indication that any energy is retained as kinetic energy of the coupled cars (they presumably come to a stop), the entire initial kinetic energy of 12,500 J is converted into heat energy.

A 5000-Kg Freight Car Having a Kinetic Energy of 2500