Question

A nail becomes hot when hammered into a plank because

• A. the potential energy of the hammer changes
  heat energy
• B. the kinetic energy of the hammer changes
  into heat energy
• C. the force of friction changes into heat energy
• D. none of the above

Answer 1

The correct option is B

the kinetic energy of the hammer changes
into heat energy

Explanation for the correct option

B: the kinetic energy of the hammer changes into heat energy

1. When the hammer is brought from the topmost position to the plank, the potential energy gets converted into kinetic energy following the law of conservation of energy.
2. This kinetic energy gained due to gain in velocity will be dissipated to nail in the form of heat energy.
3. This heat energy will increase the temperature of the nail.
4. Thus, a nail becomes hot when hammered into a plank because the kinetic energy of the hammer changes into heat energy.