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Physics - Y10 + Y11 > Energy > Flashcards

Energy Flashcards

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1
Q

What is kinetic energy

A

Energy stored in movin objects

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2
Q

How to calculate kinetic energy?

A

1/2m X m X v(2)
0.5 X mass (kg) X velocity squared (m/s)

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3
Q

What is specific heat capacity?

A

amount of energy needed to raise the temperature of 1kg of the substance by 1 C

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4
Q

Formula for energy with SHC

A

E = mc△t
change in thermal energy (J) - mass (kg) X change in temp (C) X SHC

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5
Q

What is elastic potential energy?

A

Putting energy to stretch spring, stretched spring is storing this energy called EPE

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6
Q

R/s between force applied and extension(m)

A

Straight line, directly proportional
If force if too great, it reaches limit of proportionality - inelastically deformed

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7
Q

Formula for elastic potential energy

A

E = 1/2 X k X e(2)
E = spring constant X extension (m)

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8
Q

Law of conservation of energy

A

Energy can be transferred usefully, stores or dissipated, but cant be created or destroyed

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9
Q

What is a system

A

Object/group of objects

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10
Q

What is a closed system

A

no energ ycan enter/leave

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11
Q

What is dissipated energy?

A

wasted

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12
Q

How can you reduce dissipated energy?

A

Reduce friction by:
* Lubricant eg oil
* remove air particles

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13
Q

What is gravitational potential energy

A
  • energy stored in object due to its position above the earths surface
  • due to gravity acting on object
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14
Q

Formula for gravitational energy

A

E = mgh
mass X gr/ field strength X height (m)

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15
Q

When is work done?

A

when energy is transferred from one store to another

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16
Q

What is mechanical work?

A

force to move an object

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17
Q

What is electrical work?

A

current transferring energy

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18
Q

Equation for work done

A

W = FD
Force (N) X distance (m)

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19
Q

Factors that affect how quickly a building cools down

A
  • Thermal conductivity of walls - the higher TC of material, the higher than rate of energy ransfer by conduction
  • Thick walls - reduces rate of thermal energy transfer
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20
Q

What are modern houses built of? How is it kept warm?

A
  • 2 layers: external brick and internal breezeblock
  • between there is a cavity
  • builders pack cavity with insulating material with low TC
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21
Q

Single glazed vs double glazed

A
  • single = high TC
  • double = Low TC
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22
Q

What is loft insulation

A
  • for roof
  • low TC reduces thermal energy leaving
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23
Q

What is power?

A

Rate at which energy is transferred

24
Q

Formula for power

A

P = E/T(s)

25
Q

What is 1 watt

A

energy transfer of 1j per second

26
Q

RP: SHC of a liquid

A
  1. Place beaker on balance + press 0
  2. Add liquid and record mass
  3. Place thermometer and immersion heater in liquid
  4. Read starting temp of liquid
  5. Wrap beaker in insulating foam - reduce thermal energy transfer
  6. Connect joulemeter to immersion heater and power pack
  7. Leave for 30 min
  8. Read joulemeter
  9. Read final temp of liquid
27
Q

Formula for SHC

A

c = change in energy
/
mass X temp change

28
Q

Sources for inaccuracy for SHC + improvements

A
  1. Thermal Energy passing out of beaker == use insulator with low TC
  2. Not all thermal energy passing to liquid == ensure immersion heater is fully submerged
  3. Incorrect reading of thermometer == use electronic temp probe
  4. Thermal energy not spread in liquid == stir
29
Q

Efficiency formula

A

Useful output/total input

30
Q

3 fossil fuels

A

coal, oil, gas

31
Q

Advantages of fossil fuels

A
  • Reliable
  • Release great deal of energy
  • Abundant and cheap
  • Versatile - use them for many things
32
Q

Cons of fossil fuels

A
  • Release co2 - global warming
  • non renewable - not being replensished as we us them - one day run out
  • Release other pollutants
33
Q

What does burning diesel release

A

carbon particles and nitrogen oxides

34
Q

What does burning coal release?

A

Sulfur dioxide = acid rain

35
Q

What is a renewable energy source?

A

one that is being replenished as its used

36
Q

Examples of renewable energy resources

A
  • wind power
  • solar power
  • hydroelectric power
  • tidal power
  • biofuels
  • geothermal
  • wave power
37
Q

Pros of all renewable energy resources

A
  • never run out
  • dont add co2 to atmosphere
38
Q

cons of wind and solar power

A
  • not reliable - days not windy/ cloudy
39
Q

pros and cons of hydroelectric power

A
  • reliable
  • habitats are destroyed when dams are built and valleys are flooded
  • only good is countries which have lots of rivers (not UK)
40
Q

pros of tidal power

A
  • reliable
41
Q

cons of all renewable energy resources

A
  • they only produce electricity
  • energy mostly used in transport which runs on petrol/diesel which are fossil fuels
42
Q

What is nuclear power

A
  • Non renewable
  • Run on urnamium and plutonium
43
Q

PROS of nuclear power

A
  • No co2 - doesnt contribute to climate change
  • reliable - lots of electricity when we need it
44
Q

cons of nuclear power

A
  • highly dangerous radioactive materials- - if released into environment = disastrous
  • decomissioning a power plant takes many yrs and expensive
  • produces large amount of dangerous radioactive watse - needs to be stored for thousands of yrs before its safe
45
Q

What does the UK have abundant reserves of?

A

coal
up until 1950s, all of electricity generated from coal

46
Q

What happend when nuclear power came online in the 1950s

A
  • by the 1980s, it produced around 20% of uks electricity
47
Q

Benefits of burning gas over burning coal for electricity

A
  • burning gas = less co2
  • gas fired power stations are flexible - can be swiched on quickly during periods of high demand (short start up time), coal fired power stations have a long start up time
48
Q

Econonmic factor to why politicians didnt see that fossil fuels were releasing co2

A

fossil fuels are cheap
switching away costs money and that could cost jobs

49
Q

What is the Kyoto protocal

A

countries signed up to this and comitted themsleves to reduce green house gases emissions

50
Q

Why is the UK in a good position to reduce greenhouse gas emissions

A
  • wind-farms are built here because there is lots of space
51
Q

future of uk energy

What is a baseload and which power is ideal for this?

A
  • baseload = constant supply of electricity thats on all the time
  • nuclear power - cant easily be turned on and off so tend to be on all the time, no co2 released
52
Q

future of uk energy

What can we use for power in times of emergency in peak demand

A
  • gas - fired power stations - switched on quickly
53
Q

future of uk energy

What will renewables and other sources play a role in the future?

A
  • Renewables = bulk of electricity
  • nuclear = base load
  • gas = peak demand
54
Q

SHC method for a solid

A
  1. Measure mass of block
  2. Wrap into insulating layer to reduce energy transferred from block to surroundings
  3. Add few drops of water into thermometer hole otherwise there will be an air gap
  4. Insert thermometer and heater
  5. Measure initial temp of block
  6. Set pd of power supply to 10V and start stop watch
  7. Take readings of current and temp every minute for 10 minutes
  8. Turn off power supply and calc P = VI then E = Pt to find out energy
  9. Draw energy (x) and temp (y) graph
  10. calc gradient = 1 / (gradient X mass of block)
  11. repeat and compare with diff materials
55
Q

RP 2:

Thermal insulators effectiveness of diff materials

A
  1. place small beaker in big beaker
  2. boil water and transfer 80 in small beaker
  3. cardboard for large beaker + hole for thermometer
  4. record starting temp and start stopwatch
  5. record temp every 3 min for 15 in (5 readings)
  6. repeat with same vol of water but add some insulating material to fill gap between 2 beakers
  7. test range of diff matierials with same mass (iv)

Physics - Y10 + Y11 (7 decks)

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