Defining Work and Energy

In science, work is only done when a force causes displacement in its direction (W = F × s). If you push a wall and it doesn't move, no work is done! Energy is the capacity to do work, measured in Joules.

Kinetic and Potential Energy

Kinetic Energy: The energy possessed by an object due to its motion (½mv²).
Potential Energy: Energy stored due to position or configuration. Gravitational potential energy depends on height (mgh).

Conservation of Energy and Power

The Law of Conservation of Energy states that energy can only be transformed, never created or destroyed. The sum of kinetic and potential energy (mechanical energy) remains constant in free fall. The rate at which work is done is Power, measured in Watts (1 W = 1 J/s). Commercially, large amounts of energy are measured in kilowatt-hours (kWh).