P1: Energy Flashcards
Chemical energy?
Energy stores include fuels, food or the chemicals found in betteries. The energy is transferred during chemical reactions
Kinetic Energy?
Energy stores describe the energy an object has because it is moving
Gravitational potential energy?
Energy stores are used to describe the energy stored in an object because of its position, such as an object above the ground
What happens when energy is transferred?
When energy is transferred to an object, the energy is stored in one of the objects energy stores
Kinetic energy equation?
1/2mv squared
Elastic potential energy equation?
1/2 kx squared
Gravitational potential energy equation?
mgh
Define specific heat capacity?
The amount of energy needed to raise the temperature of 1 kilogram of a substance by 1 degree Celsius
Units for specific heat capacity?
Joules/degree celsius/kilogram
Define power?
The rate at which energy is transferred
State 2 equations for power?
Power = energy transferred/time
Power = work done/time
Unit for power?
Watt (W)
Energy changes when a ball is thrown upwards?
Upwards: KE is converted to GPE
Peak: Maximum GPE, zero KE
Downwards: GPE is converted to KE
Examples of chemical energy stores?
Food
Fuel
Batteries
State 4 different energy stores?
Kinetic energy
Gravitational potential energy
Elastic potential energy
Chemical energy
State the law of conservation of energy?
Energy cannot be created or destroyed (it can only be transferred into different forms)
What is waste energy?
The energy that is not used by the device for its desired purpose
Describe energy changes that occur in a light bulb?
Electrical energy is transferred into light and heat energy
Light is a useful energy form, heat is waste energy
State 2 equations to calculate efficiency?
=Useful output energy transfer/total input energy tansfer
=useful power output/total power output
How can efficiency of a system be increased?
- Reducing waste energy
- recycling wast output
