Energy Flashcards
What are the 8 energy stores?
Gravitational Potential (GPE), Elastic Potential (EPE), Magnetic, Electrostatic, Chemical, Nuclear, Kinetic & Thermal
What are the 4 energy transfers?
Mechanically (using forces) , electrically, by heating & by radiation (light/sound)
What does the principle of conservation of energy say?
Energy can’t be created or destroyed. It can only be transferred from one store to another
What is efficiency?
The measure of how good a device is at changing energy from one store to another
How do you calculate efficiency?
Efficiency = Useful energy out/Total energy in X100
Useful = Efficiency X Total
Total = Useful / Efficiency
What are the 4 rules of sankey diagrams?
- The thickness of the arrow relates to the amount of energy - The thicker the arrow, the more energy.
- The combined thickness of all input arrows should be the same as the combined thickness of all output arrows
- The waste arrow always points down
- The types of energy should be identifies
What is the formula for work done?
Work Done = Force X Distance Moved
F = W/D
D = W/F
F = Newtons
D = Metres
- What objects have kinetic energy?
- What affects kinetic energy?
- Objects that are moving
- The mass or velocity of the object
What is the formula for kinetic energy?
Ek = 1/2 m v^2
M = (2 Ek)/v^2
V = √(2 Ek / M)
Ek = Joules
M = Kg
V = m/s
- What two things make the GPE greater?
- What is the Gravitational field strength on Earth?
- Height of objects above ground & the gravitational field strength.
- 9.81 N/kg (Shortened to 9.8 or 10)
What is the formula for GPE?
Ep = mgh
M = Ep/gh
G = Ep/mh
H = Ep/mg
Ep = Joules
M = kg
G = N/kg
H = M
- What are infinite energy sources?
- What are finite energy sources?
- Renewable energy sources will never run out, or can be regenerated
- Non-renewable energy sources will eventually run out and once used they can’t be used again.
What is the equation to find power?
P = E / T
E = P X T
T = E / P
P = Watts
E = Joules
T = Seconds
