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PhysicsKS4 Energy Homework
Booklet
Name: _________________________________________Class: _________________________________________Teacher: _______________________________________
Comprehension Task Describe what forms of energy are involved in, and how they are transferred, when you
lift your arm above your head
Read the En 01 section on your knowledge organiser before you begin.
Homework Task Due Date
Teacher Signiture
En 01 Energy stores and PathwaysEn 02 Gravitational Potential Energy & Kinetic Energy storesEn 03 Elastic Potential Energy StoresEn 04 PowerEn 05 Thermal ConductivityEn 06 Specific Heat Capacity Required PracticalEn 07 & 08 Insulation Required PracticalEn 09 EfficiencyEn 10 Renewable and & Non-renewable Energy Resources
En 01
Energy stores & Pathways R A G The 8 ways in which energy can be stored.
The 4 pathways by which energy can be transferred.
What is meant by a closed system.
What conservation of energy is.
What is meant by the term dissipation.
En 01 Energy Stores and Pathways Exam Question Practice
Q1.A child drops a ball.
The ball hits the ground and bounces.
The graph below shows the velocity-time graph for the ball from when the ball is dropped until when the ball reaches the top of its first bounce.
Air resistance has been ignored.
Comprehension Task Describe what forms of energy are involved in, and how they are transferred, when you
lift your arm above your head
(a) Describe the motion of the ball between points A and B on the graph above.
(2)
(b) What direction is the ball moving between points C and D on the graph above?
(1)
(c) The ball and the Earth form a system.
What is meant by ‘a system’? Tick one box.
A group of objects that interact.
Objects with big differences in mass.
Objects with gravitational potential energy.
(1)
(d) When the ball hits the ground, energy is transferred from the ball to the Earth.
Explain how the data in the graph above shows this energy transfer.
(4)
(Total 8 marks)
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En 02
Gravitational Potential Energy & Kinetic Energy stores R A G The equations that link Gravitational field strength, Gravitational potential energy, mass, and height.
The equations that link Kinetic energy, mass, and speed.
What happens to the GPE store of an object when it moves up or down.
What the amount of energy in a kinetic energy store depends on.
Read the EN 02 & 03, and EN 02, 03, 04 & 09 sections on your knowledge organisers before you begin.
Comprehension Task Explain, in terms of energy stores and energy transfers, what happens to the
gravitational potential energy of an object when it is lifted above your head.
Which is the correct equation to calculate gravitational potential energy (GPE)?o GPE = mass x height x gravitational field strengtho Mass = GPE x height x gravitational field strengtho Gravitational field strength = mass x height x GPE
Using the correct equation, work out the following:o Find the GPE of an object when its mass is 30kg, height is 200cm and GFS is 9.8 o Find the KE of an object when its mass is 15kg and speed is 20m/s
En 02 Gravitational Potential Energy & Kinetic Energy stores Exam Question Practice
Q1.The image below shows a student before and after a bungee jump.
The bungee cord has an unstretched length of 20 m.
(a) For safety reasons, it is important that the bungee cord used is appropriate for the student’s weight.
Give two reasons why.
(2)
(b) The student jumps off the bridge.
Complete the sentences to describe the energy transfers.
Use answers from the box.
elastic potential gravitational potential kinetic sound thermal
Before the student jumps from the bridge he has a store of
_____________________ energy.
When he is falling, the student's store of _____________________
energy increases.
When the bungee cord is stretched, the cord stores energy as
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_____________________ energy. (3)
(c) At the lowest point in the jump when the student is stationary, the extension of the bungee cord is 35 metres. The bungee cord behaves like a spring with a spring constant of 40 N / m.
Calculate the energy stored in the stretched bungee cord.
Use the correct equation from the Physics Equations Sheet.
(2)
(Total 7 marks)
Q2.The diagram shows a tennis ball thrown vertically into the air.
At position C, the ball has just left the tennis player's hand at a speed of 5.0 m/s
The tennis ball has a mass of 0.058 kg
(a) Write down the equation that links kinetic energy, mass and speed.
(1)
(b) Calculate the kinetic energy of the tennis ball at position C.
(2)
(c) At position A the tennis ball is at maximum height.
What is the gravitational potential energy of the tennis ball at position A?Ignore the effect of air resistance.
(1)
At position B the tennis ball has 0.38 J of gravitational potential energy.
(d) Write down the equation that links gravitational field strength, gravitational potential
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energy, height and mass.
(1)
(e) Calculate the height of the tennis ball above the tennis player's hand when at position B.
gravitational field strength = 9.8 N/kg
(3)
(Total 8 marks)
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En 03
Elastic Potential Energy stores R A G How to calculate the energy stored within an elastic potential store using the equation:
Elastic potential energy = 0.5 x spring constant x (extension)2
What an elastic potential energy store is.
The effect that doubling the extension of a spring has on the energy stored within the spring.
Read the EN 02 & 03, and EN 02, 03, 04 & 09 sections on your knowledge organisers before you begin.
Comprehension Task Describe the elastic potential store of energy in an elastic band, and how it changes
when the band is stretched.
If you double the extension of a spring, what happens to the energy stored within it? If you were to extend it further, what may occur?
Which definition correctly describes sublimation?o Elastic potential energy = 0.5 x spring constant x (extension)2 .o 0.5 = Elastic potential energy x spring constant x (extension)2 .o Elastic potential energy = 0.5 x spring constant x (extension) .
En 03 Elastic Potential Energy stores Exam Question Practice
Q1.The figure below shows a student before and after a bungee jump.
The bungee cord has an unstretched length of 20.0 m.
The mass of the student is 50.0 kg.
The gravitational field strength is 9.8 N / kg.
(a) Write down the equation which links gravitational field strength, gravitational potential energy, height and mass.
(1)
(b) Calculate the change in gravitational potential energy from the position where the student jumps to the point 20.0 m below.
(2)
(c) 80% of this change in gravitational potential energy has been transferred to the student’s kinetic energy store.
How much has the student’s kinetic energy store increased after falling 20.0 m?
(1)
(d) Calculate the speed of the student after falling 20.0 m.
Give your answer to two significant figures.
(4)
(e) At the lowest point in the jump, the energy stored by the stretched bungee cord is 24.5 kJ.
The bungee cord behaves like a spring.
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Calculate the spring constant of the bungee cord.
Use the correct equation from the Physics Equation Sheet.
(3)
(Total 11 marks)
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En 04
Power R A G What is meant by the term Power.
The equations that link energy transferred, Power, and time.
The equations that link Power, time, and Work done.
How that time taken to transfer energy affects Power.
Read the EN 02, 03, 04 & 09 section on your knowledge organisers before you begin.
Comprehension Task Define the terms ‘Power’ and ‘Work Done’.
Calculate the work done by this box being moved 2m. Ensure you write the correct equation first.
En 04 Power Exam Question Practice
Q1.The diagram shows a climber part way up a cliff.
(a) Complete the sentence.
When the climber moves up the cliff, the climber
gains gravitational ______________________ energy.
(1)
(b) The climber weighs 660 N.
(i) Calculate the work the climber must do against gravity, to climb to the top of the cliff.
(2)
(ii) It takes the climber 800 seconds to climb to the top of the cliff.During this time the energy transferred to the climber equals the work done by the climber.
Calculate the power of the climber during the climb.
(2)
(Total 5 marks)
Q2.Figure 1 shows a cyclist riding along a straight, level road at a constant speed.
Figure 1
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(a) Complete the sentences.
As the cyclist rides along the road, the _______________________ energy store in
the cyclist’s body decreases. The speed of the cyclist is constant when the work done
by the cyclist is _______________________ the work done against air resistance.
(2)
Figure 2 shows how the speed changes as the power output of the cyclist changes.
Figure 2
(b) Write down the equation that links power, time and work done.
(1)
(c) Calculate the work done by the cyclist when his power output is 200 W for 1800 seconds.
(3)
(d) Calculate the percentage increase in speed of the cyclist when the power output changes from 200 W to 300 W.
(2)
(e) The maximum speed this cyclist can travel on a level road is 14 m/s.
How does cycling uphill affect the maximum speed of this cyclist?
Explain your answer.
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(3)
(Total 11 marks)
En 05
Thermal Conductivity R A G What is meant by thermal conductivity.
The effect of higher thermal conductivity on the energy transferred by a material.
The effect of lower thermal conductivity on the energy transferred by a material.
Read the En 05 & 07 section on your knowledge organisers before you begin.
Comprehension Task Different materials have different thermal conductivity – what does thermal
conductivity mean, and give an example of a good and poor thermal conductor?
The diagram shows a metal bar being heated up – the ions increase their vibration as more energy is supplied. Explain what would happen to the ions if cold water was poured over the bar.
En 05 Thermal Conductivity Exam Question Practice
Q1.A student investigated the properties of three insulating materials. Figure 1 shows the apparatus the student used.
Figure 1
In the investigation, different insulating materials were used to insulate a metal can filled with hot water.
Figure 2 shows how the temperature measured by the thermometer changed over 25 minutes for each of the materials.
Figure 2
(a) What was the temperature of the room where the student carried out the investigation? Tick one box.
20 °C 38 °C 53 °C 80 °C
(1)
(b) Material C has the highest thermal conductivity. How does the graph in Figure 2 show this?
(1)
(c) Another student repeated the investigation using the equipment shown in Figure 3.
Figure 1 shows the first set of equipment used.
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Figure 1 Figure 3
Suggest how using the equipment in Figure 3 will have affected the student's results.
(2)
(d) The students could have used a temperature probe and datalogger instead of a thermometer.
Figure 4 shows the datalogger screen and the thermometer.
Figure 4
Complete the sentences. Choose the answers from the box.
higher lower the same
Compared to the thermometer, the datalogger and temperature probe have a
resolution that is ____________________ . Compared to the thermometer, the
chance of misreading the datalogger and temperature probe is
____________________ .
(2)
(e) The table gives information about four types of insulation that could be used in the walls of houses.
Type of insulation Thermal conductivity in W/m °C
Felt wool 0.070
Mineral wool 0.040
Polyurethane foam 0.030
Rock wool 0.045
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Tick one box.
Felt wool
Mineral wool
Polyurethane foam
Rock wool
Give a reason for your answer.
(2)
(Total 8 marks)
Q2.A gas burner is used to heat some water in a pan.
Of the energy released by the burning gas by the time the water starts to boil:
60% has been transferred to the water.
20% has been transferred to the surrounding air.
13% has been transferred to the pan.
7% has been transferred to the gas burner itself.
(a) Use the above information to complete the pie-chart.
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(3)
(b) Some of the energy released by the burning gas is wasted.
(i) What happens to this wasted energy?
(2)
(ii) What percentage (%) of the energy from the gas is wasted?
(1)
(Total 6 marks)
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En 06
Specific Heat Capacity Required Practical R A G What is meant by Specific Heat Capacity of a substance.
How to calculate the amount of energy stored within a substance using the equation:
Change in thermal energy = mass x specific heat capacity x temperature change.
The unit used to represent Specific Heat Capacity.
Read the En 06 section on your knowledge organisers before you begin.
Comprehension Task What is temperature?
Which is the correct definition of specific heat capacity?
a. The amount of energy needed to raise the temperature of 1 kg of substance by 1°C.
b. The amount of heat needed to raise the temperature of 1 kg of substance by 1°C.
c. The amount of energy needed to raise the temperature of 10 kg of substance by 1°C.
On a hot summer’s evening, if you lean against a brick wall you will find that it’s quite warm – why?
En 06 Specific Heat Capacity Required Practical Exam Question Practice
Q1.The electric kettle shown below is used to boil water.
©leeser87/iStock
(a) After the water has boiled, the temperature of the water decreases by 22 °C.
The mass of water in the kettle is 0.50 kg.
The specific heat capacity of water is 4200 J/kg °C.
Calculate the energy transferred to the surroundings from the water.
(2)
(b) Why is the total energy input to the kettle higher than the energy used to heat the water?
Tick (✔) one box.
Tick (✔)
Energy is absorbed from the surroundings.
Energy is used to heat the kettle.
The kettle is more than 100% efficient.
(1)
(Total 3 marks)
Q2.The specific heat capacity of aluminium can be determined by experiment.
(a) Draw a labelled diagram showing how the apparatus used to determine the specific heat capacity of aluminium should be arranged.
(3)
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(b) Describe how you could use the apparatus you drew in part (a) to determine the specific heat capacity of aluminium.
(6)
(c) Methods used to determine the specific heat capacity of aluminium may give a value greater than the actual value.
Explain why.
(2)
(Total 11 marks)
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En 07 & 08
Insulation Required Practical & Analysis R A G How to measure the thermal conductivity of a material.
The effect of different materials on the energy transferred from an object.
The effect of layers of materials on the energy transferred from an object.
How thermal conductivity of a material can be used to reduce the energy lost from a building.
Methods of insulating buildings to reduce energy loss.
Read the En 05 & 07 section on your knowledge organisers before you begin.
Comprehension Task Looking at where you live, describe the different ways that are used to prevent heat
loss in the winter
Soldiers in the British Army have their uniform designed to come in ‘layers’ – why would this help when working outdoors in the winter (talk about energy transfer)?
En 07 & 08 Insulation Required Practical & Analysis Exam Question Practice
Q1.(a) The diagram shows a ski jacket that has been designed to keep a skier warm.
The jacket is made from layers of different materials.
(i) The inner layer is shiny to reduce heat transfer.
Which process of heat transfer will it reduce?
(1)
(ii) Why is the layer of fleece good at reducing the transfer of heat from a skier’s body?
(1)
(b) A student tested four different types of fleece, J, K, L and M, to find which would make the warmest jacket. Each type of fleece was wrapped around a can which was then filled with hot water.The temperature of the water was taken every two minutes for 20 minutes.
The graph shows the student’s results.
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(i) In each test, the water cooled faster during the first five minutes than during the last five minutes. Why?
(1)
(ii) To be able to compare the results, it was important to use the same volume of water in each test.
Give one other quantity that was the same in each test.
(1)
(iii) Look at the graph line for fleece K.
Estimate what the temperature of the water in the can wrapped in fleece K would be after 40 minutes.
(1)
(iv) Which type of fleece, J, K, L or M, should the student recommend to be used in the ski jacket? Give a reason for your answer.
(2)
(Total 7 marks)
Q2.An electric immersion heater is used to heat the water in a domestic hot water tank.When the immersion heater is switched on the water at the bottom of the tank gets hot.
(a) Complete the following sentence.
The main way the energy is transferred through the copper wall of the water tank is
by the process of ________________________________________ .
(1)
(b) The immersion heater has a thermostat to control the water temperature.
When the temperature of the water inside the tank reaches 58°C the thermostat switches the heater off. The thermostat switches the heater back on when the temperature of the water falls to 50°C.
Graph A shows how the temperature of the water inside a hot water tank changes with time. The tank is not insulated.
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Time in hours
(i) The temperature of the water falls at the fastest rate just after the heater switches off. Explain why.
(2)
(ii) To heat the water in the tank from 50°C to 58°C the immersion heater transfers 4032 kJ of energy to the water. Specific heat capacity of water = 4200 J/kg°C
Calculate the mass of water in the tank.
(3)
(iii) An insulating jacket is fitted to the hot water tank.
Graph B shows how the temperature of the water inside the insulated hot water tank changes with time.
Time in hours
An insulating jacket only costs £12.
By comparing Graph A with Graph B, explain why fitting an insulating jacket to a hot water tank saves money.
(3)
(Total 9 marks)
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En 09
Efficiency R A G What is meant by the term efficiency.
The equations that link efficiency, useful output energy transfer, and total input energy transfer.
The equations that link efficiency, useful power output, and total power input.
[H] How to increase the efficiency of a named energy transfer.
Read the En 02, 03, 04 & 09 section on your knowledge organisers before you begin.
Comprehension Task Describe the wasted energy from a mechanical and an electrical device in your home.
Using your answers above, how could you reduce the energy wasted in these devices?
En 09 Efficiency Exam Question Practice
Q1.The image shows a man using a leaf blower to move some leaves.
The leaf blower is powered by an electric motor connected to a battery.
(a) Energy transfers take place when the leaf blower is being used.
Use the correct answer from the box to complete each sentence.
chemical electrical kinetic nuclear sound
The battery stores _____________________ energy which is transferred into electrical energy.
The electric motor transfers electrical energy usefully into _____________________ energy.
The motor wastes energy as _____________________ energy and as energy that heats the surroundings.
(3)
(b) The total power input to the leaf blower is 750 W.The useful power output of the leaf blower is 360 W.
Calculate the efficiency of the leaf blower.
(2)
(Total 5 marks)
Q2.The table gives data about two types of low energy bulb.
Type of bulb Power inputin watts
Efficiency Lifetimein hours
Cost ofone bulb
Compact FluorescentLamp (CFL) 8 20% 10 000 £3.10
Light Emitting Diode 5 50 000 £29.85
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(LED)
(a) Both types of bulb produce the same useful power output.
(i) Calculate the useful power output of the CFL.
Show clearly how you work out your answer.
(2)
(ii) Calculate the efficiency of the LED bulb.
Show clearly how you work out your answer.
(1)
(b) LED bulbs are expensive. This is because of the large number of individual electronic LED chips needed to produce sufficient light from each bulb.
(i) Use the data in the table to evaluate the cost-effectiveness of an LED bulb compared to a CFL.
(2)
(ii) Scientists are developing brighter and more efficient LED chips than those currently used in LED bulbs.
Suggest one benefit of developing brighter and more efficient LED chips.
(1)
(Total 6 marks)
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En 10
Renewable & Non-renewable Energy Resources R A G What energy resources are used in modern societies.
What is meant by a non-renewable energy resource.
What is meant by a renewable energy resource.
Why some energy resources are more reliable than others.
The main energy resources used by humans.
Environmental impacts of using certain energy resources.
Examples of political, social, ethical, and economic reasons that may stop scientists from preventing environmental impacts of energy resource usage.
Read the En 10 section on your knowledge organisers before you begin.
Comprehension Task Explain one effect that burning fossil fuels has on the environment, and one way that
that effect could be reduced (assuming the amount of fossil fuel burnt was the same).
Draw one line from each energy source in List A to the statement about the energy source in List B.
List AEnergy source
List B
Statement about energy source
Uses energy from falling water
Geothermal
Uses energy from inside the Earth
Hydroelectric
Is unpredictable
Nuclear
Produces dangerous waste
En 10 Renewable & Non-renewable Energy Resources
Q1.Electricity can be generated using various energy sources.
(a) Give one advantage and one disadvantage of using nuclear power stations rather than gas-fired power stations to generate electricity.
(2)
(b) (i) A single wind turbine has a maximum power output of 2 000 000 W.
The wind turbine operated continuously at maximum power for 6 hours.
Calculate the energy output in kilowatt-hours of the wind turbine.
(2)
(ii) Why, on average, do wind turbines operate at maximum power output for only 30% of the time?
(1)
(c) An on-shore wind farm is made up of many individual wind turbines.
They are connected to the National Grid using underground power cables.
Give one advantage of using underground power cables rather than overhead power cables.
(1)
(Total 6 marks)
Q2.The pie charts show the relative proportions of electricity generated in Japan from different energy sources in 1975 and 2005.
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(a) Describe the main differences in the energy sources used in 2005 compared with 1975.
(1)
(b) In the UK, nuclear fuels are used to generate about 21% of the total electricity supply.
(i) What is the name of the process by which a nuclear fuel produces heat?
(1)
(ii) Explain how the heat released from a nuclear fuel is used to generate electricity in power stations.
(2)
(iii) Some people have suggested that more nuclear power stations should be built in the UK.
Give two reasons to support this suggestion.
(2)
(iv) Nuclear power stations create dangerous waste.
Why is the waste from a nuclear power station dangerous?
(1)
(c) A headline from a newspaper article is shown below.
Explain the possible link between climate change and coal-burning power stations.
(2)
(Total 9 marks)
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