Open System: Exchanges both matter and energy with surroundings. | Closed System: Exchanges energy but not matter with surroundings.

Kinetic Energy: Energy of motion, depends on mass and velocity. | Potential Energy: Energy of position/configuration, depends on position or deformation.

Gravitational PE: Energy due to height. $U_g = mgh$ | Elastic PE: Energy stored in a spring. $U_{sp} = \frac{1}{2}kx^2$

Work: Energy transferred by a force acting over a distance. | Power: Rate at which work is done or energy is transferred.

A system that allows both matter and energy to be exchanged with its surroundings.

A system that allows energy exchange but not matter exchange with its surroundings.

Work is when a force moves an object over a distance; calculated as $W = Fd$.

The capacity to do work; it comes in many forms (kinetic, potential, thermal, etc.).

The sum of kinetic and potential energy in a system.

Energy of motion; calculated as $K = \frac{1}{2}mv^2$.

Energy due to height above a reference point; calculated as $U_g = mgh$.

Energy stored in a spring or elastic material; calculated as $U_{sp} = \frac{1}{2}kx^2$.

The rate at which work is done or energy is transferred; calculated as $P = \frac{W}{t}$ or $P = \frac{\Delta K}{t}$.

The object's energy changes (typically kinetic energy, according to the Work-Energy Principle).

Elastic potential energy is stored in the spring.

The object gains gravitational potential energy.

Mechanical energy is converted to thermal energy, reducing the object's kinetic energy and/or potential energy.

The total energy of the system increases.