Topic 1 - energy Flashcards
(12 cards)
1
Q
What are the different stores of electricity?
A
- thermal
- kinetic
- gravitational potential
- elastic potential
- chemical
- magnetic
- electrostatic
- nuclear
2
Q
What happens when a system changes?
A
- system means single object or group of objects being focused on
- when a system changes - energy is transferred (into or away from system, between different objects etc)
3
Q
What is a closed system?
A
- systems where neither matter nor energy can enter or leave
- net change in total energy of closed system is always 0
4
Q
How can energy be transferred by heating?
A
- water is system - energy transferred to water (by kettles heating element) by heating - into waters thermal energy store - causes temperature of water to rise
- energy transferred electrically to thermal energy store of kettles heating element - transfers energy by heating to waters thermal energy store
5
Q
What is work done?
A
energy transferred
6
Q
How is friction work done?
A
- friction between cars brakes and wheels do work as it slows down
- energy transferred from wheels kinetic energy stores to thermal energy store of surroundings
7
Q
How does a ball dropped do work?
A
- ball ropped from height is accelerated by gravity - gravitational force does work
- energy transferred from balls gravitational potential energy store do kinetic energy store
8
Q
What is air resistance?
A
- air resistance acts against all falling objects
- causes energy to be transferred to other energy stores
9
Q
What is specific heat capacity?
A
amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celcius
10
Q
Specific heat capacity experiment?
A
- measure mass of block - wrap in insulating layer to reduce unwanted energy transfers to surroundings
- measure initial temp. of block - set voltage of power supply to 10v - turn on power supply - start stopwatch
- ten minutes - stop stop watch - temperature will still rise even though heater has been turned - record highest temperature reached - calculate temperature rise -
- calculate energy transferred by using P = IV to calculate power, and E = Pt to calculate energy
- use formula specific heat capacity = E/mass x theta
11
Q
What is the conservation of energy principle?
A
energy can be transferred usefully, stored or dissipated, but never created or destroyed
12
Q
What is power?
A
- power is the rate of energy transfer
- it is measured in watts - one watt = 1 joule of enegry transferred per second
