Which of the following is the SI unit of energy?

• A. $Joules$
• B. $Watt$
• C. $meterspersecond$
• D. $Newtons$

Answer: (A)

Verified step by step guidance

1. Understand that energy is a physical quantity that represents the capacity to do work or produce heat.
2. Recall that the SI unit of energy is derived from the fundamental units of mass, length, and time.
3. Recognize that the joule (J) is defined as the energy transferred when a force of one newton moves an object one meter in the direction of the force.
4. Express this relationship mathematically as \(\text{Joule} = \text{Newton} \times \text{meter} = (\text{kg} \cdot \text{m/s}^2) \times \text{m} = \text{kg} \cdot \text{m}^2 / \text{s}^2\).
5. Compare the options given: watt is a unit of power, meters per second is a unit of speed, and newtons is a unit of force, so the correct SI unit of energy is joules.