Topic 8

• A system that experiences no net change in its total energy when energy transfers occur within it.

  Closed System
• Energy that is transferred to, and spread out in, the surroundings. It is usually in the form of heat, and is a result of a system undergoing a rise in temperature.

  Dissipation of Energy
• The ratio of useful output energy transfer to total energy input. It can never exceed 1 (or 100%), due to the conservation of energy.

  Efficiency
• The rate at which energy is transferred, or the rate at which work is done. It is calculating by dividing the work done by the time taken.

  Power
• When a force oppresses an object‘s motion, the moving object will do the work against it.

  Resistive Force
• The unit of power. It is equal to one joule per second.

  Watt
• Work done on an object when a force causes it to move through a distance. It is equal to the product of the distance travelled and the magnitude of force in the direction of motion.

  Work Done