Energy conservation

Definition

Energy conservation is the principle stating that the total energy in an isolated system remains constant over time. Energy can neither be created nor destroyed, only transformed from one form to another.

5 Must Know Facts For Your Next Test

1. The total mechanical energy (kinetic + potential) in a closed system is conserved if only conservative forces are acting.
2. Conservative forces, such as gravity and spring force, do not dissipate mechanical energy.
3. Non-conservative forces like friction convert mechanical energy into thermal or other non-mechanical forms of energy.
4. Potential energy depends on the position of an object within a force field, such as gravitational or elastic fields.
5. $$E_{total} = K + U$$ where $$E_{total}$$ is the total mechanical energy, $$K$$ is kinetic energy, and $$U$$ is potential energy.

Review Questions

• What happens to the total mechanical energy in a system with only conservative forces?
• How does friction affect the conservation of mechanical energy?
• Write the equation that represents the total mechanical energy in a system.

Related terms

Kinetic Energy: The energy possessed by an object due to its motion, given by $$K = \frac{1}{2}mv^2$$ where $$m$$ is mass and $$v$$ is velocity.

Potential Energy: The stored energy of an object based on its position or state. Examples include gravitational potential energy and elastic potential energy.

Conservative Force: A force that does no net work on an object moving around a closed path; it conserves mechanical energy within a system. Examples include gravitational force and spring force.