Chapter 1 - Energy Flashcards
Name 8 energy stores
Kinetic
Gravitational potential
Elastic potential
Thermal
Chemical
Nuclear
Magnetic
Electrostatic
4 ways energy can be transferred
Heating
Waves
Electricity
Forces (mechanical(
Work done equation
Force x distance
Work done unit
Joules
Force unit
Newton
Distance unit
Metres
An objects gravitational potential energy depends on three things
- Height above ground
- Gravitational field strength
- Mass
Gravitational potential energy =
Mass x gravitational field strength x height
Mass unit
Kilograms
Gravitational field strength unit
N/Kg
Kinetic energy depends on 2 things
Mass and speed
Kinetic energy =
0.5 x mass x speed squared
Speed unit
M/s
Elastic potential energy =
0.5 x spring constant x extension squared
Spring constant unit
N/m
Power is defined as
How work done per second
Power unit
Watt
1 watt =
1 joule per second
Power =
Energy transferred
______________________
Time
Lubrication =
Reducing unwanted energy transfer due to friction
Streamlining =
A way of reducing energy wasted due to air resistance or drag
Efficiency equation =
Useful output energy transfer
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Total input energy transfer
Describe energy transfer when a car slows down
Energy transferred mechanically from kinetic store of the car to the thermal store of the brakes
Describe energy transfer when an electric kettle heats water
Electric current in a kettle transfers energy to the heating element’s thermal store.
Energy is then transferred from the heating element to the thermal store of the water
Describe the energy transfer when a ball is fired using an elastic band
Energy is transferred mechanically from the elastic store of the band to the kinetic store of the ball
Describe the energy transfer when a battery powered toy car is used
Energy transfer is transferred electrically from the chemical store of the battery to the kinetic store of the toy car
