CP3 Conservation of Energy Flashcards
What is mass measured in?
Kilograms (Kg)
What is energy measured in?
Joules ( J )
Conservation of Energy
Energy can not be created or destroyed; Energy can only be transferred from one store to another.
What is Energy Efficiency?
A way of describing how good a device is at transferring energy into useful forms.
What’s the equation for energy efficiency?
Efficiency = useful energy transferred / total energy
Name two things that affect the rate of energy transfer.
- Thickness of material
- Temperature difference
Thermal Conductivity
A measure of how well a material conducts energy when it is heated
What does a high thermal conductivity mean?
The material is good at conducting thermal energy
What is the equation for Kinetic Energy?
KE = 0.5mv^2
Kinetic Energy = 0.5 * Mass * Velocity^2
What is Kinetic Energy measured in?
Joules
Convert 250g into Kg
250g = 0.25kg
250 / 1000 = 0.25
What kind of diagram do we use to show energy transfers?
Sankey Diagram
What is a ‘System’ when we talk about energy transfers?
A set of things being studied - for example a kettle, the water in it, and it’s surroundings form a simple system.
An object or a group of objects that interact.
Dissipated
Spread out
Conduction
The way energy is transferred through solids by heating.
Vibrations are passed from particle to particle.
Convection
The movement of particles in a fluid depending on their temperature.
Hotter, less dense regions rise, and cooler, denser regions sink.
Emit
To give out
What does it mean if an energy source is non-renewable?
It will eventually run out because we cannot renew our supplies of it.
What does is mean if an energy source if renewable?
It will never run out
Name all 8 energy stores
- Magnetic
- Thermal
- Elastic potential
- Gravitational potential
- Nuclear
- Electrostatic
- Chemical
- Kinetic
Define Thermal Energy Store and give an example
The energy a system has because of its temperature.
An example could be that the thermal store of water in a kettle increases when you turn the kettle on.
Define Kinetic Energy Store and give an example of one
The energy a system has because it’s moving.
An example could be that if a car speeds up from 30km/h to 60km/h then its kinetic energy store will increase.
Define Gravitational Potential Energy Store and give an example of one
The energy a system has because of how high it is above the ground.
An example could be: if you pick up an object off the ground, its gravitational potential will increase.
Define Chemical Energy Store and give an example
The energy stored in chemicals including food, fuels, and batteries.
An example could be: If you turn on a battery powered torch, the chemical energy stored in the battery will decrease.
