Chapter 9, Problem 1RQ

Why does a penny become warmer when struck by a hammer?

To determine

The reason that a penny becomes warm when a hammer strikes on it.

Answer to Problem 1RQ

The penny becomes warmer due to the generation of heat energy when a hammer strikes it.

Explanation of Solution

On continuously hammering on the penny makes hotter due to the generation of heat energy. The atoms inside the penny are compressed due to the blow caused by a hammer resulting in breaking of metallic bond in the metal matrix. Due to this, the heat due to the hammer blow is conserved in the form of kinetic energy.

The kinetic energy is directly related to the temperature, this result in the increase in the temperature of the penny.

Conclusion:

Therefore, the penny becomes hotter due to the heat generation when a hammer strikes on it.