Energy stores and transfers Flashcards
1
Q
Equation for kinetic energy
A
KE = 1/2 X m X v^2
2
Q
Law of conservation of energy
A
Energy can not be created of destroyed, only transferred between stores
2
Q
Equation for GPE
A
change in GPE = m X g X change in h
3
Q
what are the 4 energy transfers
A
Mechanical, Electrical, Heating, Radiation
3
Q
Efficiency equation
A
Efficiency = useful energy transferred by device (J) / total energy supplied to device (j)
4
Q
How can you prevent unwanted energy transfers
A
lubrication and insulation (less transfer to thermal store for both)
5
Q
Fossil fuels
A
- cause pollution
- will eventually run out (non-renewable)
6
Q
Renewables
A
- high initial costs but little running cost
- look bad
- little/no pollution
- unreliable
7
Q
Biofuel
A
- decreases food supply
- needs a lot of land to get fuel
- carbon neutral at small scale
- reliable
