Science Physics P1.2

Science Physics P1.2

1. Forms of energy 2.1

   • Energy exists in different forms such as light, sound,kinetic (movement), nuclear, electric, gravitational potential, elastic potential and chemical
   • Energy can be transferred from one form to another form
   • When a object falls it gains speed, is gravitational potential energy decreases and its kinetic energy increases

2. Useful energy 2.3

   • Useful energy is energy in the place we want it and the form we want it. wasted energy is energy that is not useful
   • Useful energy and wasted energy both end up being transferred to the surroundings, which become warmer
   • As energy spreads out it gets more and more difficult to use for further energy transfers

3. Conservation of energy 2.2

   • It is not possible to create or destroy energy.
   • Its only possible to transfer it from one form to another or one place to another
   • Conservation of energy applies to all energy changes

4. Energy and efficiency 2.4

   • No machine can be 100% efficient. Energy is measured in Joules
   • Measurements to make machines more efficient include reducing : friction,air resistance, electrical resistance, noise due to vibrations
   • Efficiency= useful energy transferred by the appliance x100 total energy supplied to the appliance