SP3 Conservation of Energy Flashcards
(43 cards)
What is the law of conservation of energy?
Energy can be stored, transferred between stores, and dissipated, but it cana never be created or destroyed.
What are the 8 energy stores?
- Kinetic
- Thermal
- Chemical
- Gravitational Potential
- Elastic Potential
- Nuclear
- Magnetic
- Electrostatic
(King Timothee Came Galloping Enthusiastically Near Mount Etna)
What is kinetic energy?
Energy in a moving object
Kinetic energy (J) =
KE =
0.5 x Mass (kg) x Velocity ² (m/s) ²
0.5 x m x v²
What is thermal energy?
Energy in any object (more in a heated object)
What is chemical energy?
Anything that can release energy by a chemical reaction
What is gravitational potential energy?
Anything in a gravitational field.
Raised objects store energy in GPE stores.
The higher the object is lifted, the more energy is transferred to this store.
Δ Gravitational Potential Energy (J) =
Δ GPE =
Mass (kg) x Gravitational Field Strength (N/kg) x Δ Vertical Height (m)
m x g x Δh
What is elastic potential energy?
Anything stretched e.g. springs, rubber bands
What is nuclear energy?
Energy in the nucleus of an atom (aka atomic energy)
What is magnetic energy?
Energy between magnets of different poles
What is electrostatic energy?
E.g. two charges that attract and repel each other
What are the 4 energy transfers?
- Radiation
- Mechanical
- Electrical
- Heating
(Red Motorbikes Excite Humans)
What is radiation as an energy transfer?
Energy transferred by waves
What is mechanical as an energy transfer?
A force acting on an object and doing work
What is electrical as an energy transfer?
A charge doing work
What is heating as an energy transfer?
Energy transferred from a hot to cold object
Efficiency =
Useful energy transferred by the device (J) / Total energy supplied to the device (J)
Given as a number between 0 and 1
The higher the number, the more efficient the machine.
What are the 3 methods of heat trasnferal?
- Conduction
- Convection
- Radiation
What is conduction?
- Happens in solids
- Happens because of vibrations of particles due to heating
- The vibration moves along the material, moving the heat energy
What is convection?
- Happens in liquids and gases
- Hot material rises and spreads out
- This creates a cycle called a convection current
What is radiation?
- Doesn’t need particles (can travle through a vacuum)
- Is infrared rays
- Travels in straight lines
What is a conductor?
Material where heat and electricity can pass through easily
What is an insulator?
Material where heat and electricity can’t pass through easily