Unit 1 - Energy Flashcards
(17 cards)
What is the conservation of energy?
Energy cannot be created or destroyed, only transferred. It is measured in Joules (J)
What are the types of energy stores?
-Kinetic energy
-Gravitational potential energy
-Thermal energy
-Elastic potential energy
What is kinetic energy?
Energy of moving objects. The faster an object is moving, the more kinetic energy it has. It is calculated using the equation E = ½mv², Where E = kinetic energy (J), m = mass (kg) and v = speed (m/s)
Can be rearranged for the equation 2E = mv²
What is Gravitational potential energy?
The energy stored by an object when it is above the Earth. The higher up something is, the more GPE it has. It is calculated using the equation E = mgh where E = Change in GPE, m = mass (kg), g = gravitational field strength and m = change in height (m)
What is Elastic potential energy?
The energy stored by objects that are stretched or squashed. It is measured using the equation E = ½Ke², where E = elastic potential energy (J), K = spring constant (N/m) and e = extension (m)
What is thermal energy?
The energy within a system responsible for its temperature. It is measured using the equation ΔE = mcΔT where ΔE = change in thermal energy (J), m = mass (kg), c = specific heat capacity and ΔT = change in temperature.
What energy is the same as sound/vibrational energy?
Kinetic energy
What energy is stored in food, fuels and cells/batteries?
Chemical potential energy
Why is energy transferred?
When objects interact in a system and energy is transferred from one store to another or between objects.
What happens between energy transfers in a closed system (no energy transferred to or from surroundings)?
The energy stores are equal, for example if an object falls, its GPE at the top is equal to the KE at the bottom.
What are the types of energy transfers?
-Heating
-Electrically
-Radiation
-Mechanically
What is power?
The rate of energy transfer. The equation is P = E/t, where P = power in watts, E = energy transferred in Joules, and t = time in seconds
What is efficiency?
The ratio of total energy that is converted to useful energy.
How does insulation work?
Thermal energy is is usually lost from buildings through conduction (vibrations passing along particles) which transfers energy to outside surroundings. Insulations, such as double glazing, reduce this.
What is an energy source?
Where we harness energy from the world.
What are examples of energy sources?
-Fossil fuels
-Nuclear power
-Wind power
-Hydroelectric
-Solar power
