What is defined as the capacity of a body to do work?

The capacity of a body to do work is defined as energy. Energy can exist in various forms, such as kinetic, potential, thermal, and chemical, and it is the measure of the ability to perform work or produce change. For example, when an object is lifted against gravity, it possesses potential energy due to its elevated position, which can be converted to kinetic energy if it falls. This broad definition encapsulates the fundamental understanding that energy is a critical component in performing tasks and driving processes in both mechanical systems and natural phenomena.

The other terms listed have specific definitions that relate to energy but do not capture its overall essence as the capacity to do work. Power, for instance, is the rate at which work is done or energy is transferred, thereby linking energy with time. Pressure refers to the force exerted per unit area, significant in fluid mechanics but not directly tied to the ability to do work. Force is an interaction that causes an object to change its velocity, effectively related to energy but not defining it. Therefore, the most accurate answer highlighting the capacity to do work is energy.