How is work defined in physics?

Work in physics is defined as the process of energy transfer that occurs when a force acts on an object and causes it to move a certain distance. It is mathematically expressed as the product of the force applied to the object and the displacement it causes, particularly when the force is applied in the direction of the displacement. Therefore, when a force causes displacement, work is done.

Understanding work in this context is fundamental to mechanics and is key in applications involving energy transfer, such as lifting an object against gravity or pushing an object across a surface. The concept emphasizes both the application of a force and the movement resulting from that force, thus linking force and motion to the energy involved in doing work.

The other definitions provided do not accurately represent the concept of work in physics. Energy transferred without a force does not involve work, while the product of mass and acceleration relates to force rather than work. Lastly, the rate of energy use refers to power, not work. Hence, the choice that correctly identifies the definition of work is the one that highlights the relationship between force and displacement.