Energy Flashcards
Imagine pushing a car along a road
You must apply a force
And you push the car a certain distance
Work Done
Work done (J) = force (n) x distance (metres)
Energy transfer
As you push the car, you transfer energy from your body to : the car - increasing its kinetic energy The surroundings (and bits of the car) heat up because of friction
The amount of work you do =
The amount of work you do = The amount of energy transferred
Power =
Power =Work done / time taken
One watt
Is one joule per second
Method of power and workdone experiment
- Measure vertical step
- Count number of steps
- Weigh yourself
- Time yourself running up stairs
Power and work done
Power = workdone/time = (force x distance) / time
Kinetic energy =
Kinetic energy (J) = 1/2 x
2
mass x velocity
Time =
Time = 1/ frequency
Power measured in
Watts (w)
Mass measured in
Kg
Frequency measured in
Hz
Distance measured in
Metres
Time period
Seconds
Work done measured in
Joules
Gravitational potential energy =
Gravitational potential energy = mass Gravitational field strength x height
Energy transfer
Toaster
Electrical heat to -> heat, light + kinetic
Energy can’t be
Energy can’t be created or destroyed it can only change from one form to another
Efficiency
Efficiency= useful energy out/ total energy in
Doing work
When you push or pull something and make it move you do work
Different forms of energy
Thermal Light Gravitational potential Electrical Elastic potential Kinetic Sound Chemical Nuclear
Thermal
The energy of an object due to its temp
Light
Energy in the form of visible electromagnetic radiation
Gravitational potential
The energy of an object due to its height
Electrical
The energy transferred by an electric current
Elastic potential
Energy stored in a stretched or squashed object
Kinetic
Energy possessed by a moving object
Sound
Energy possessed by a moving object
Sound
Energy possessed by a moving object
Food
Chemical
Heat saving devices
Draught excluders
Double glazing/curtains
Roof insulation
Carpets
