# Shared Flashcard Set

## Details

P1a.2
Physics, Core (P1, A2), Using Energy
11
Physics
06/19/2008

Term
 What are 6 forms of Energy?
Definition
 Chemical energy: Energy is released when chemical reactions take place.Kinetic energy: The energy of a moving objectGravitational and Potential energy: Energy of an object due to it's position. Elastic/Strain energy: Energy stored in a springy object when we stretch and squash it. Electrical energy: Energy transferred by an electrical current. Thermal energy: Energy of an object due to its temperature.
Term
 What is conservation of energy?
Definition
 Conservation of energy says that energy cannot be created or destroyed.
Term
 What energy changes occur when we turn on a torch?
Definition
 Chemical energy in Battery > Electrical energy > Light energy + Thermal energy
Term
 What energy changes occur on a roller coaster as it descends?
Definition
 Gravitational potential energy > Kinetic energy (+ Sound) + thermal energy
Term
 What is energy? What is it measured in?
Definition
 The ability to do work. It is measure in Joules (J)
Term
 What is useful and wasted energy?
Definition
 Useful energy is energy transferred to where it is wanted in the form it is wanted. Wasted energy is the energy that is not usefully transferred or transformed. E.G. Using a drill, particularly a blunt one, creates lots of heat. However, we only want to create a hole so the heat is wasted energy.
Term
 What happens to energy eventually?
Definition
 It is transferred to the surroundings. The energy become less useful the more it spreads out.
Term
 What is power?
Definition
 Power = Work or energy/ Time
Term
 Why does a pendulum eventually stop swinging?
Definition
 Because of a small amount of wasted energy on sound and air resistance.
Term
 How do we work out efficiency?
Definition
 Efficiency = (Useful energy transferred by the device) / (Total energy supplied to the device)You can write the answer as a decimal or x 100 to get the percentage efficiency.
Term
 How can we show energy transfer where energy is wasted?
Definition
 [image]A Sankey Diagram.
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