Energy Flashcards

1
Q

Force applied and extension of springs relationship

A

They are directly proportional to each other but there is a limit of proportionality

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2
Q

What happens after you reach the limit of proportionality to the spring

A

The spring will not return to its original length

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3
Q

Law of conservation of energy

A

Energy can be transferred usefully, stored or dissipated but it cannot be created or destroyed

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4
Q

What is a system

A

A group of objects

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5
Q

friction acts on a pendulum as it passes through the air what is the result of this
What happens to the pendulums movement
(4)

A

The friction causes energy to be transferred to thermal energy

air around the fixed point where the pendulum is hanging from gets gradually warmer

These stores of thermal energy are less useful. The energy has been dissipated (wasted). This will cause the pendulums to gradually swing with less energy and eventually stop.

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6
Q

How could we reduce the loss of energy by friction by a pendulum

A

Lubricant oil or removing the air particles.

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7
Q

Describe the transfers of energy when a bungee jumper jumps

(6)

A

At the start of the jump, all of the energy in the system is in the store of GPE

As the jumper falls the GPE store converts into KE store

When the bungee rope just starts to tighten, the kinetic energy store is now at its maximum

When the rope is fully extended the KE store is 0 because the jumper is no longer extending all the energy has been transferred into EPE store. The bungee jump then recoils and is transferred from the EPE store back to the KE store.

As the jumper goes up the KE store would be transferred back into GPE store.

At the top all of the energy is now in the GPE store

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8
Q

Why would a bungee jumper not go back into the same original position as they jumped off (3)

A

This is because the energy is dissipated as thermal energy. Due to friction with air particles. It is also due to stretching effects in the bungee rope which is not fully elastic.

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9
Q

Work is done when?

A

Energy is transferred from one store to another

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10
Q

Mechanical work meaning

A

Using a force to move an object

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11
Q

Work done equation

A

Force * distance

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12
Q

How do brakes work

A

The brake presses against the wheel

This creates friction between the brake and the wheel

The KE energy store of a car is transferred to thermal energy store in the brakes.

The temperature of the brake increases and the car slows down

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13
Q

Factors that affect the cooling of a building

A

The high the thermal conductivity of a material, the high the rate of the energy transfer by conduction across that material.

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14
Q

What are modern houses walls built of

A

External brick and internal breezeblock and between the walls there is a cavity.

Builders pack the cavity with insulating material which has very low thermal conductivity.

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15
Q

Single glazed windows property

A

High thermal conductivity

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16
Q

Double glazed thermal conductivity

A

Low thermal conductivity

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17
Q

Loft insulation thermal conductivity

A

Has a low thermal conductivity reducing the rate of which thermal energy transfers through

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18
Q

How should a UK house be built and why

A

Construct the building with a low thermal conductivity

Build the house with thick walls as this also reduces the rate of thermal energy transfer

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19
Q

Practical specific heat capacity
step 1 and 2

A
  1. Place a beaker on a balance and press zero
  2. Now add oil to the beaker and record the mass of the oil
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20
Q

Practical specific heat capacity
step 3 and 4

A

Place a thermometer and an immersion heater into the oil

Read the starting temperature of the oil

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21
Q

Practical specific heat capacity
step 5 and 6

A

Wrap the beaker in insulating foam to reduce thermal energy transfer to the surroundings

Connect a joule meter and to the immersion heater

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22
Q

Practical specific heat capacity
step 7, 8 and 9

A

Wait for 30 minutes

Read the total number of joules of energy that passed into the immersion heater

and read the final temperature of the oil

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23
Q

Practical specific heat capacity step 10

A

Use the data you have gathered to find the specific heat capacity

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24
Q

(fix the problem practical) not all thermal energy passing into the oil

A

Ensure that immersion heater is full submerged

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25
(fix the problem practical) Thermal energy passing out the beaker into the air
Use an insulator with a lower thermal conductivity
26
(fix the problem practical) Incorrect reading of the thermometer
Use an electronic temperature probe.
27
(fix the problem practical) Thermal energy not being spread through the oil
Stir the oil
28
Thermal insulation practical step 1 and 2
First we place a small beaker inside a larger beaker We then use a kettle to boil some water.
29
Thermal insulation practical step 3 and 4
Next we transfer 80 cm^3 of the hot water into the small beaker We then use a piece of cardboard as a lid for the large beaker and the lid must have a hole to insert a thermometer
30
Thermal insulation practical step 5 and 6
Next we place a thermometer through hole in a cardboard lid The bulb of the thermometer must be in the hot water
31
Thermal insulation practical step 7 and 8
Now we record the starting temp of the water and start a stopwatch At this point we need to record the temperature of the water every 3 minutes for 15 minites
32
Thermal insulation practical step 9 and 10
Next we repeat the experiment using the same volume of hot water. How ever this time we use an insulating material to fill the gap between the two beakers use the same mass of each material
33
What is the independent variable for the thermal insulation practical
Insulating material
34
The dependent variable is
The one that is measured for each change in the independent variable
35
The dependent variable is thermal insulation practical
The temperature
36
Control variables are
We don't allow to change
37
The control variable is thermal insulation practical
Mass of insulating material volume of water
38
For the practical thermal insulation how could we make the graph
By using cooling curves for different insulators Water will cool down most slowly with the most effective insulating material
39
Water will cool down most slowly with the most effective insulating/non-insulating material?
Insulating
40
Newspaper practical step 1
Start with a beaker containing 80cm^3 of hot water and add a thermometer to it
41
Newspaper practical step 2
Measure the temperature of the water every 3 minutes for 15 minutes
42
Newspaper practical step 3
Then repeat the experiment but this time we wrap two layers of newspaper around the beaker like this.
43
Newspaper practical step 4
Then repeat the experiment two more times using four layers then six layers of news paper
44
Independent variable of newspaper practical
Number of layers of newspaper
45
dependent variable of newspaper practical
Temperature
46
Control variable
Starting temperature of the water and volume of the water
47
Why is it that the more layers of newspaper, the slower the water cools down.
because more layers is more effective thermal insulator than fewer layers
48
Uses for energy
Transport Generating electricity Heating
49
Fossil fuels mainly are
Coal oil gas
50
Fossil fuel advantages (4)
Fossil fuels are reliable. They always provide energy when we need it Fossil fuels release a great deal of energy. Fossil fuels are abundant and are relatively cheap Fossil fuels are extremely versatile
51
Fossil fuel disadvantages
Burning fossil fuels release a huge amount of amount carbon dioxide Fossil fuels are non-renewable. They are not being replenished as we use them Diesel: Carbon dioxide particles and nitrogen oxides Coal: Sulfur dioxide leads to acid rain Fossil fuels can also release other pollutants
52
What do nuclear power plants run on
uranium 235 and plutonium 239
53
Nuclear power is non-rewnewable/renewable
Non-renewable
54
Advantages of using nuclear power
No carbon dioxide is released Nuclear power does not contribute to climate change Nuclear power is extremely reliable. It generates a lot of electricity exactly when we want it.
55
Disadvantages of nuclear power
Nuclear power plants contain highly dangerous radioactive material if there is an accident then these materials could be released into the environment Decommission a nuclear power plants takes many years and is extremely expensive A nuclear power plant generates large amounts of highly dangerous radioactive waste. This must be stored for thousands of years before it is safe
56
What did the UK largely for electricity before the 1950's
We used reserves of coal and burned it.
57
Why did the UK stop using coal for electricity
Int he 1950s nuclear power came online and by the 1980s this produced around 20% of the UKs electricity
58
Switch from coal to gas advantages
Burning gas generates less carbon dioxide than burning coal. This contributes to less climate change. Gas-fired power stations are flexible. They can be switched on quickly during periods of high demand (short start-up-time). Coal-fired power stations have a very long start-up time.
59
In the 1970s carbon dioxide emissions from human activity could be leading to ____ ______ At the time _______ didn't really see it as that much of a big issue
Climate change, politicians
60
What committed countries to reducing green house gas emissions
The 2005, Kyoto protocol.
61
What kind of power has the uk invested a lot into over the last decade
Wind power. Since the uk has one of the best wind locations in the world.
62
The future of UK energy we need a base load a constant supply of electricity that on all the time what kind of energy is ideal for this and an emergency power type of energy is required
Nuclear power and gas fired power stations to provide emergency power in times of peak demand
63
The future of UK energy summary
Renewable will provide the bulk of our electricity, with nuclear providing a base-load and then gas providing electricity during peak demand.
64
Renewable energy
Is one that is being or can be replenished as it is used.
65
Renewable energy sources
Wind power, solar power, hydroelectric power, tidal power, bio fuels, geothermal, wave power,
66
Advantages of renewable energy rescource
Never run out Once in place, renewable energy resources to not add any carbon dioxide to the atmosphere they do not contribute to climate change.
67
Two renewable that are not reliable
Solar power and wind power are not reliable some days are not simply windy and solar panels do not work well on cloudy days
68
Hydroelectric advantage and disadvantage
It is very reliable however habitats are destroyed when dams are built and valleys are flooded.
69
Tidal power is reliable/not reliable
Extremely reliable
70
Disadvantage of tidal power
However there are proposals to build a tidal barrage across the severe estuary but some people argue that this would be harmful to wildlife
71
Wave power UK
Is reliable and has huge potential in the UK which has an extensive coastline
72
Geothermal energy
Uses heat from the earth to generate electricity and heat buildings
73
Geothermal energy advantages + info about uk
Is reliable but is not really used very much in the united kingdom
74
A lot of renewable energy sources produce only electricity why is this a problem for the UK
A lot of energy is used in the uk is all for transport, including cars. Almost all cars in the UK run on petrol, or diesel which are fossil fuels
75
Biofuels why are they carbon neutral
Biofuels are produced from plant materials Burning bio fuels does not add extra carbon dioxide
76
Problem with bio fuels
If we use land to grow crops for fuel that could make food more expensive