Yr.9 Physics - Energy Types

What are the different types of energy stores?

Kinetic, Magnetic, Chemical, Gravitational, Thermal, Nuclear, Elastic, Electrostatic

What is the principle of Conservation of Energy?

Energy cannot be created or destroyed, only transferred.

What unit is energy measured in?

Joules (J)

What are the four methods of energy transfer between stores?

Mechanically, Electrically, Heating, Radiation

How is efficiency calculated?

Efficiency = Useful output energy (or power) / Total output energy (or power)

In a Sankey diagram, where does useful energy, wasted energy and input energy go?

Useful energy goes on the right. Wasted energy goes on the right and downwards (or upwards). Input energy goes on the left.

How is power calculated?

Power = Work done / Time taken

What unit is power measured in?

Watts (W)

What is Gravitational potential energy?

Gravitational potential energy is the energy stored in an object as the result of its vertical position or height.

What is the equation for calculating gravitational potential energy?

EGPE = mgh (Gravitational Potential Energy = mass x gravitational field strength x height)

What is the equation for calculating kinetic energy?

Ek = ½ mv2 (Kinetic energy = 0.5 x mass x velocity squared)

How do roller coasters work in terms of energy conversion?

All roller coasters work by converting gravitational potential energy to kinetic energy.

When objects are stretched, where is the work/energy stored?

The energy is stored as Elastic Potential Energy.

What is the equation for calculating elastic potential energy?

Work done = ½kx2 (k is the spring constant, x is the extension)

What does the spring constant, k, represent?

The spring constant, k, tells you how much force, in Newtons, is required to stretch a material by 1m.