What is the term for the energy of things in motion?

The correct term for the energy of things in motion is kinetic energy. Kinetic energy specifically refers to the energy an object possesses due to its motion. This energy can vary based on the mass of the object and its velocity, and it is calculated using the formula KE = 1/2 mv², where m is the mass and v is the velocity of the object.

Potential energy, on the other hand, is related to an object's position or state, such as gravitational potential energy, which is determined by height above a reference point. Mechanical energy encompasses both kinetic and potential energy within a system, making it a broader term. Thermal energy relates to the internal energy of an object due to the kinetic energy of its particles, which is a different concept focused on temperature and heat transfer.

In essence, kinetic energy is the specific term used to describe energy due to motion, clearly distinguishing it from other types of energy associated with different states or conditions.