Science Y10: Kinetic & Potential Energy

Energy

“the ability to do work.”

Law of Conservation of Energy:

Energy cannot be created or destroyed; it can only be transferred or transformed.

Kinetic Energy (Movement)

Energy of motion — depends on an object’s speed and mass.
Examples:

• Mechanical Energy – energy in an object due to its motion or vibration.

• Thermal Energy – energy contained in the movement of an object’s particles.

• Sound Energy – energy carried by waves that cause the molecules of a material to vibrate.

• Light Energy – energy of photons, produced when an object’s atoms heat up.

• Electrical Energy – energy from the movement (flow) of electrons.

Potential Energy

Potential Energy (Stored)

Energy stored due to an object’s position or condition.
Examples:

• Elastic Potential Energy – energy stored when an object is stretched or compressed (e.g. spring).

• Gravitational Potential Energy – energy an object has due to its position in a gravitational field (depends on mass, height, and gravity).

• Chemical Energy – energy stored in chemical bonds (released during chemical reactions like combustion).

• Nuclear Energy – energy stored in the nucleus of an atom (released during nuclear fission or fusion).

Energy Transfers and Transformations

• Energy Transfer: Energy passed from one object to another.
  Example: kicking a soccer ball (kinetic energy transferred from foot → ball).

• Energy Transformation: Energy converted from one form to another.
  Example: toaster transforming electrical energy → thermal energy.

Energy Efficiency

Energy Efficiency

• Energy Efficiency Formula:

  Efficiency=  [Useful Energy Output / Total Energy Input] × 100

• Example:
  A light bulb radiates 10 W of light energy for every 60 W of electrical energy supplied.

  Efficiency= 10 / 60 = 0.17 or 17%

• Interpretation: Only 17% of the energy is useful light — the rest is wasted as heat.