thequarkyteacher.files.wordpress.com · Web view4.05describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of

Edexcel ScienceiGCSE Physics

E. Fundamentals of Energy2019-2020

Name:________________Physics Teacher:______________

House CG

Year 9

Specification Checklist

4.01 use the following units: kilogram (kg), joule (J), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s) and watt (W)

4.02 describe energy transfers involving energy stores:

• energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear

• energy transfers: mechanically, electrically, by heating, by radiation (light and sound)

4.03 use the principle of conservation of energy

4.04 know and use the relationship between efficiency, useful energy output and total energy output:

efficiency=useful energyoutputtotalenergy input

4.05 describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of the above relationship, including their representation by Sankey diagrams

4.13 know and use the relationship between gravitational potential energy, mass, gravitational field strength and height:

gravitational potential energy = mass × gravitational field strength × height

GPE = m × g × h

4.14 know and use the relationship:

kinetic energy = 12 x mass x velocity2

KE=12×m×v2

4.15 understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work

Fundamentals of Energy – Science (Physics) 2

Key WordsKey Word Image Definition

Conservation The value is kept constant before and after a change.

Efficiency The percentage of energy that is used for a useful task and how much is wasted.

Energy Store A form of energy that can be stored

Energy Transfer

A form of energy that results in one energy store becoming another type of energy store.

Gravitational Potential

The energy stored in an object by raising it up high. If it fell down to the ground all of this would be converted into kinetic/heat.

Insulation Material or process that prevents the transfer of heat by conduction, convection or radiation.

Joule The unit for energy. [J]

Kinetic Movement energy

Mass The quantity of matter in a body. It is measured in kg

Sankey Diagram

A visual representation of the conservation of energy that shows how much energy is useful and how much energy is wasted from a give input.

Thermal Heat energy.


1: Forms of Energy

Task: Energy Mind Map


ENERGY

Learning Outcomes:

1. Identify the 8 energy stores2. Identify the 4 forms of energy transfers3. Describe the difference between an energy store an an energy transfer

Forms of Energy

For example: How is energy transferred when an electrical car accelerates?

Key Ideas

1. There are 8 forms of energy store: thermal, kinetic, chemical, nuclear, elastic, gravitational potential energy, electrostatic and magnetic.

2. There are 4 forms of energy transfer:a. By mechanical meansb. By electricityc. By radiation (light and sound)d. By heating

3. The energy stores are types of energy which can be stored in a system.4. The energy transfers are the mechanisms by which these stores are transferred from

one form into another.


Worksheet – Forms of Energy

Worked Example: What are the energy stores/transfers involved when a trolley rolls down a ramp?

Initial Energy Store Energy transferred by: Final Energy Store(s)

Questions

Situation Initial Energy Store Energy transferred by: Final Energy Store(s)

Burning a Candle

Rubbing your hands together

Sled sliding down a hill

Releasing a catapult.

Using a battery powered torch

A battery powered motor

lifting a load


Chemical Energy (fuel)

E1.Energy Transfers and Stores in a Steam EngineYour teacher will demonstrate how a steam engine canbe used to lift a mass.

In the space below, create a diagram to show how the energy is stored and transferred during the process.

You can use boxes to represent energy stores:

You can use labelled arrows to represent energy transfers:

By heating (burning fuel)


Health and Safety Check!

Steam engine can get hot during use. Do not touch.

Mass may fall during demonstration. Keep feetaway from landing zone.

2: The Conservation of Energy

Knowledge and Understanding QuizUse the knowledge you have gained since the start of Shell to answer the following questions.

1. Name 3 types of energy store.

……………………………………………………………… (3)

2. Name the 4 ways energy can be transferred?

…………………………………

…………………………………

…………………………………

………………………………… (4)

3. What energy stores/transfers take place when a bike rolls down a hill?

Initial Energy Store Energy transferred by: Final Energy Store(s)

(3)

4. What are the two sets of units that can be used to measure density?

………………………………………………………………………………………… (2)

5. What is the equation linking pressure difference, depth, density and g?

………………………………………………………………………………………… (1)

6. Identify a part of the EM spectrum that is dangerous and name one of the dangers

that it poses.

………………………………………………………………………………………… (2)

Score [ /15]


Learning Outcomes:

1. Describe what is meant by the conservation of energy2. Identify the form of the useful and wasted energy store in different situations3. Draw and interpret a Saneky diagram and describe how it shows the

conservation of energy.

The Conservation of Energy

Key Ideas

1. Conservation of Energy: Energy cannot be created or destroyed in any process. (It is just transferred from one form to another).

2. This means that the total amount of energy you put into a process must come out the other side.

3. Energy is measured in Joules [J].4. Energy that comes out of a process may be useful but it can also be wasted.


5. For example: When you use a lamp, useful energy is transferred by light while energy is also wasted by heating the surroundings.

E2. Useful and Wasted EnergyAround the room are a number of different systems and processes that use energy usefully. Each of the systems also wastes energy.

In the table below, describe each system briefly and then identify the form of the useful and wasted energy.

What is energy measured in?

……………………………………….

System Useful Energy Output Wasted Energy Output


Health and Safety Check!Keep water away from Electrical Appliances.

Put-Put boat containsan open flame. Do not touch.

Kettle has boiled and contains hot water.

Sankey Diagrams

Key Ideas

1. Sankey diagrams are a visual way to represent how much energy is useful and how much energy is wasted by a system.

2. Each branch of the Sankey diagram should be labelled with the form of the energy and the amount of energy. The form can be a store or a transfer.

3. The wider the arrow, the more energy it represents.

Worked Example1. A light bulb is supplied with 100J of energy electrically. It transfers 30J as light waves

and the rest is transferred to the thermal energy store of the surroundings. Draw a Sankey diagram to represent this.


Worksheet: Sankey Diagrams

1. An inefficient light bulb. The input energy is 10 J transferred electrically. The useful output energy is 4 J as light and the wasted energy is 6 J to the thermal store of the surroundings.

2. A candle. The input chemical energy store is 200 J. The useful output energy transfer is 140 J to the thermal energy store and 60J is transferred by sound waves.

Score: Markers comments:


3: Efficiency

Knowledge and Understanding Quiz

Use the knowledge you have gained so far to answer the following questions:

1. An electric heater is supplied with 500J electrically. 400J of this is transferred usefully

into the thermal energy store of the room, but 100J is wasted (transferred as light

waves). Sketch a Sankey diagram below to represent this.

(3)

2. What is the definition of a longitudinal wave?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

3. How much force is required to create a pressure of 560Pa over an area of 0.25m2?

……..………….. (3)

4. What is the centre of gravity?

………………………………………………………………………………………… (1)

5. What is the unit for frequency?

………………………………………………………………………………………… (1)

Score [ /10]


Learning Outcomes:

1. Know that efficiency is a measure of how much energy is transferred into useful energy in a system.

2. Use the equation:

Efficiency=Useful EnergyOutputTotal Energy Input

3. Calculate Efficiency from a Sankey Diagram.

Efficiency

Key Ideas

1. Efficiency, useful energy output and total energy input are linked in the equation:


2. Efficiency must be a value between 0 and 1 but it can be turned into a percentage by multiplying by 100.

3. Useful energy output and total energy input must have the same unit prefix.

Worked Examples1. A light bulb is supplied with 80J electrically. If it emits 20J of this energy as light

waves, what is the efficiency of the light bulb?

2. A hairdryer is labelled as being 70% efficient. If it is supplied with 3000J, how much useful energy does it give out?


Worksheet – The Efficiency EquationComplete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. What is the efficiency of a light bulb that transfers 600J of light energy to the surroundings when it is supplied with 950J of electrical energy?

…………………..

2. An iPod uses 400J of chemical energy if 225J is transferred as sound energy, what is the efficiency of the device?

…………………..

3. A TV is supplied with 1000J of electrical energy. It transfers out 300J of energy as sound and 375J as light. What is the efficiency of the TV?

…………………..

4. A microwave is 75% efficient. If it is supplied with 2000J of electrical energy, how much energy will it usefully transfer to thermal energy?

…………………..

5. A kettle is 96% efficiency. If it is supplied with 3000J of electrical energy, how much of that is transferred as useful thermal energy?

…………………..

6. A plant gets 200J of light energy from the sun. If the plant is 0.5% efficient, how much of that light energy goes into photosynthesis?

…………………..

7. A light bulb is rated as 40% efficient. How much electrical energy does the bulb need to be supplied with to give out 80J of light energy?

…………………..


8. A toaster is rated as 85% efficient. If you need 700J of thermal energy to toast your bread, how much electrical energy do you need to give the toaster?

…………………..

9. A computer is 65% efficient. If the computer usefully emits 40J as sound energy and 90J as light energy, how much electrical energy has it been supplied with?

…………………..

10. A light bulb is supplied with 800J of electrical energy. If it wastes 500J as thermal energy, how efficient is the light bulb.

…………………..

11. A kettle is supplied with 3kJ of electrical energy. If 100J of energy is wasted as sound energy, how efficient is the kettle?

…………………..

12. Petrol supplies a car with 25MJ of chemical energy. The car turns 600kJ of this into useful kinetic energy. How efficient is the car?

…………………..13. How much energy would need to be supplied to an oven that uses 5kJ of energy to

cook your food. The oven is 68% efficient.

…………………..14. A light bulb is 60% efficient. If it is supplied with 2kJ of energy, how much of that

energy is converted into heat?

…………………..15. A TV is supplied with 2.5kJ of energy. If it wastes 40% of the energy it is given as

thermal energy. How much energy is turned into light and sound?

…………………..


Efficiency and Sankey Diagrams

Key Ideas

1. You could be asked to calculate efficiency from a Sankey diagram.2. The total input energy is represented by the total height of the Sankey diagram. 3. Remember: Useful energy is represented by the arrow pointing to the right.

Worked Example1. Below is a Sankey diagram for a petrol powered car. Can you calculate the efficiency

of the car using the Sankey diagram?


Worksheet – Efficiency and Sankey DiagramsFor each of the Sankey diagrams below, calculate the efficiency of the system. You must show all of your working [equation, substitution, solution and units]

1.

Efficiency = …………………..2.

Efficiency = …………………..

3.



4.


5.


6.



4: Gravitational Potential Energy


Use the knowledge you have gained since the start of Shell to answer the following

questions.

1. An electric heater is supplied with 500J of electrical energy. 400J of this is transferred

into useful thermal energy but 100J is wasted as light energy. What is the efficiency

of the heater?

……..………….. (3)

2. What is the definition of a transverse wave?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

3. An object has a density of 600g/cm3 and takes up a volume of 25cm3. What is the

mass of the object?

……..………….. (3)

4. Define Hooke’s Law.

………………………………………………………………………………………… (2)

5. What is the unit for wavelength?

………………………………………………………………………………………… (1)

Score [ /11]


Learning Outcomes:

1. Calculate GPE using the equation:GPE=m× g×h

2. Rearrange the equation to calculate an objects height or mass. 3. Investigate what effect the GPE of an object has on it’s final speed.

Gravitational Potential Energy

Key Ideas

1. Gravitational Potential Energy (GPE) is dependent on two factors:a. How high you are off the groundb. How large your mass is.

2. We can calculate GPE using the following equation:GPE=m× g×h

3. To use the above equation, mass must be measured in kilograms [kg] and height must be measured in meters [m]. This will give GPE in Joules [J].

4. g = 10 N/kg

Worked Examples1. A 2kg book is kept on a shelf 2 meters above the ground. How much gravitational

potential energy does the book have?

2. A 600g bird has 1500J of gravitational potential energy. How high above the ground must the bird be?


Worksheet – Gravitational Potential EnergyComplete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. How much GPE is gained by a man of mass 90kg when he climbs up stairs of height 3m?

…………………..

2. Calculate the GPE gained by a bird of mass 2kg when it climbs up by 2000m.

…………………..

3. What is the GPE gained by a fly of mass 2g when it flies up by 6m?

…………………..

4. Calculate the height gained by a van, of mass 2500kg, if it gains 100 000J of GPE.

…………………..

5. What is the height gained by a bird, of mass 500g, if it gains 300J of GPE?

…………………..

6. Calculate the mass of a fly if it gains 0.2J of GPE when it climbs up by 20m.

…………………..


7. Calculate the mass of a car if it gains 50kJ of GPE when it climbs up a hill of height 25m.

…………………..8. Calculate the height gained by a girl, of mass 50kg, if she gains 2.5kJ of GPE.

…………………..

9. What is the mass of a bird if it gains 200J of GPE when it climbs up by 1000cm.

…………………..

10. Calculate the gravitational field strength in a place where a child of mass 20kg gains 100J of GPE when climbing up a height of 3m.

…………………..

11. Harder: Calculate the GPE gained by a fly of weight 0.05N when it climbs up a height of 200mm.

…………………..

12. Harder: Calculate the weight of a child if they gain 700J of GPE when they climb up stairs of height 3.5m.

…………………..


E3. GPE and Final SpeedIn this investigation you are going to investigate what effect the GPE of an object has on its final speed. You will be doing this by changing the height of an object.

What is the equation linking GPE, mass, height and g?

What equipment will you use to measure each of the following variables:

1. Mass: …………………..

2. Height: ………………….

Method

1. Set up the apparatus as per the diagram. Make sure you set the light gate up at least 0.5m above the ground.

2. Attach a small piece of modelling clay to one end of the card.

3. Measure the mass of your interrupt card with the modelling clay using the balance.

4. Measure the length of your interrupt card and use this to programme the data logger [see below].

5. Begin by holding your card 10 cm (0.1m) above the light gate.

6. Drop the card 3 times, using the light gate to measure speed in each case.

7. Calculate an average. 8. Repeat steps 5-7 for a variety of

heights above the light gate.

Use the space below to take notes on how to programme the data logger for the light gate.


Health and Safety Check!Be careful when holding card up high. Do notstand on chairs.

Results

Value of g : ………………… N/kg

Mass of card and clay: …………………………. kg

Height above light

gate [m]

Final speed of card [m/s]

Average final speed

[m/s]

Change in GPE of card

[J]

Attempt 1 Attempt 2 Attempt 3

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0


Plot a graph of final speed against GPE on the graph below (speed on the y-axis, GPE on the x-axis)

Use your results to answer the following questions.

1. What is the link between final speed and an objects GPE?

……………………………………………………………………………………………………..……………………………………………………………………………………………………..……………………………………………………………………………………………………..

2. What form of energy store does the card have while it is falling?

……………………………………………………………………………………………………..

3. What was the control variable in this investigation? [variable kept constant]

……………………………………………………………………………………………………..

4. How does a light gate work?

……………………………………………………………………………………………………..……………………………………………………………………………………………………..……………………………………………………………………………………………………..……………………………………………………………………………………………………..


5: Kinetic Energy



questions.

1. A plane of mass 500kg is flying 3050m above the ground. How much gravitational

potential energy does the plane have?

……..………….. (3)

2. What is the definition of time period?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

3. A sound wave is moving at 340m/s. If it has a wavelength of 0.2m, what is the

frequency of the sound wave?

……..………….. (3)

4. Describe what is meant by elastic behaviour.

………………………………………………………………………………………… (2)

5. Name 2 forms of energy store and 1 form of energy transfer.

………………………………………………………………………………………… (3)

Score [ /12]


Learning Outcomes:

1. Calculate kinetic energy using the equation:

KE=12×m×v2

2. Rearrange the equation to calculate an objects mass or velocity. 3. Understand that to increase the kinetic energy of an object you must increase

either the mass or the speed (velcoity).

Kinetic Energy

Key Ideas

1. Kinetic energy (KE) is dependent on two factors:a. The mass of the object.b. The velocity (speed) of the object.

2. We can calculate KE using the following equation:

KE=12×m×v2

3. To use the above equation, mass must be measured in kilograms [kg] and velocity (speed) must be measured in meters per second [m/s]. This will give KE in Joules [J].

4. Don’t forget to square root when calculating velocity.

Worked Examples1. A 2kg book is falling from a shelf at a constant velocity of 10m/s. How much

kinetic energy does the book have?

2. A cyclist has 1kJ of kinetic energy and has mass of 75kg. How fast is the cyclist travelling?


Worksheet – Kinetic EnergyComplete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. Calculate the kinetic energy of a car of mass 800kg moving at a speed of 10m/s.

…………………..

2. What is the kinetic energy of a person of mass 60kg moving at a speed of 2m/s?

…………………..

3. Calculate the kinetic energy of a lorry of mass 2000kg moving at a speed of 6m/s.

…………………..

4. What is the mass of an orange that has a kinetic energy of 5J when moving at 10m/s?

…………………..

5. Calculate the mass of a missile that has a kinetic energy of 10 000 000J when moving at 200m/s.

…………………..

6. How fast is a lorry of mass 3000kg moving if it has 15 000J of kinetic energy?

…………………..


7. Calculate the speed of a car of mass 800kg that has 6 400J of kinetic energy.

…………………..8. Calculate the kinetic energy of an apple of mass 150g moving at a speed of 6m/s.

…………………..

9. Calculate the speed of a car of mass 1400kg that has 2800J of kinetic energy.

…………………..

10. What is the mass of a car that has a kinetic energy of 72kJ when moving at 12m/s?

…………………..

11. Calculate the speed of a pebble of mass 200g that has 10J of kinetic energy.

…………………..

12. Calculate the mass of a car that has a kinetic energy of 50kJ when moving at 10m/s.

…………………..13. What is the speed of a bullet of mass 30g that has 3MJ of kinetic energy?

…………………..


6: Linking GPE and KE



questions.

1. A runner is moving at 6m/s and has a mass of 65kg. What is the kinetic energy of the

runner?

……..………….. (3)

2. What is the definition of frequency?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

3. A seagull has 2.4kJ of GPE and has a mass of 2kg. How high up is the seagull?

……..………….. (3)

4. In what direction does friction always act?

………………………………………………………………………………………… (1)

5. What two parts of the EM spectrum are used for cooking?

………………………………………………………………………………………… (2)

Score [ /10]


Learning Outcomes:

1. Apply the conservation of energy to systems involving KE and GPE2. Understand and use the relationship:

GPElost=KEgained3. Carry out an investigation to test the above relationship.

Linking GPE and KE

Key Ideas

1. Due to the conservation of energy when an object is falling or moving downhill we can say that the GPE it loses must be equal to the KE it gains.

2. This can be expressed mathematically:

GPElost=KEgainedm× g×h=12×m×v2

3. To use the above relationship we must assume that no energy is lost to the surroundings.


Worked Examples1. A 1.5kg ball is dropped from a height of 6m. At what speed does the ball hit the

ground?

2. An 800kg rollercoaster car free falls from a height of 90m to a height of 20m before applying the brakes. What is the speed of the car when it reaches a height of 20m?

3. A 0.5kg tennis ball is hit directly upwards at a speed of 40m/s. What is the maximum height reached by the tennis ball?


Worksheet – Linking KE and GPEComplete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. A diver, of mass 40 kg, climbs up to a diving platform 1.25 m high.a. How much GPE does the diver gain?

b. He dives off the platform. What is his KE when he hits the water?

c. How fast must he be travelling when he enters the water?

2. Another diver, of mass 40 kg, now climbs up to a diving platform 5m high.a. How much GPE does this diver gain?

b. He dives off the platform. What is his KE when he hits the water?

c. How fast must he be travelling when he enters the water?


3. A 2kg stone is dropped from a window 5 m high. At what speed does it hit the ground?

…………………..

4. While on a rollercoaster, Mr Pocknell drops his 250g glasses from a height of 45m. At what speed will they hit the ground?

…………………..

5. Mr Daville throws an 800g rugby ball directly upwards at a speed of 20m/s. What is the maximum height of the ball?

…………………..

6. Ron (Ms Jayne’s 8kg puppy) parachutes out of plane 1km above the ground. He deploys his parachute 400m above the ground. At what speed was Ron going when he deployed his parachute?

…………………..

7. Mr Galsworthy jumps off the highest diving board into a pool for a dare. The board is 20m above the water. At what speed does Mr Galsworthy hit the water?

…………………..


E4: Conservation of Energy

In this investigation you are going to be investigating the conservation of energy.

What is the conservation of energy?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

What two equations are you going to need for this investigation?

Method

1. Set up the apparatus as shown in the diagram below. 2. Measure the length of your interrupt card.3. Programme the light gate to measure the speed of the object just before the

end of the ramp. 4. Measure the mass of your trolley using a balance5. Set the height of the ramp to 10cm. 6. Measure the height of your ramp where the light gate is.7. Release trolley 3 times8. Record values of speed from the data logger.9. Repeat steps 6 and 7 for multiple trolley heights.10.Use your results to compare GPE lost and KE gained.


Health and Safety Check!

I will ensure the trolley isstopped safely

Results

Mass of trolley: ……………. KgHeight of trolley when passing light gate: ……………….mValue of g: …………….N/kg

Height of trolley at start [m]

GPE of trolley at start [J]

GPE of trolley at light gate

[J]

GPE lost by

trolley [J]

Velocity of trolley [m/s]Average velocity of trolley

[m/s]

KE gained

by trolley

[J]1 2 3

0.10

0.15

0.20

0.25

0.30

0.35

Compare the values in the shaded columns.

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

Why might these results not be equal?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………


Stretch Activity – Complex Sankey Diagrams Sankey Diagrams can get very complex for much larger systems. Look at the examples below:

Can you sketch your own Sankey diagram for a complex system? For example: When you eat dinner and use that to power muscles that turn on a light bulb which emits light?!


Stretch Activity – Design a Rollercoaster


Stretch Activity – Rearranging Formulae The ability to rearrange complex formulae is a key skill in Physics. Below are 3 sets of formulae [getting harder from left to right]. Choose 3 formulae from each section and rearrange them to make n the subject.


1.

2.

3.

1.

2.

3.

1.

2.

3.

Fundamentals of Energy

Past Paper Questions


Q1. This question is about an electric kettle.

(a) The Sankey diagram represents the energy transfers taking place when the kettleheats some water.

What is the efficiency of the kettle?(1)

A 0.1

B 0.9

C 200

D 1800

(b) Why does the heating element in the kettle get hot when its electrical supply isswitched on?

(2) ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. .................................................................................................................................

(Total for question = 3 marks)


Q2. The photograph shows a small aeroplane, of mass 600 kg.

This aeroplane has an electric motor powered by fuel cells.

Fuel cells use hydrogen gas and provide an electric current.

(a) When the aeroplane is working, the energy changes are(1)

A chemical → electrical → kinetic

B electrical → chemical → kinetic

C electrical → kinetic → chemical

D kinetic → chemical → electrical

(b) The velocity of the aeroplane is 28 m/s.(i) State the equation linking kinetic energy, mass and velocity.

(1)

(ii) Calculate the kinetic energy of the aeroplane.(2)

Kinetic energy = ........................................................... J


(c) The aeroplane takes off and climbs to a height of 1000 m.(i) State the equation linking gravitational potential energy (GPE), mass, g and height.

(1)

(ii) Calculate the gravitational potential energy gained by the aeroplane.(2)

GPE of the aeroplane = ........................................................... J



Q3. The photograph shows equipment used for generating electricity from renewable sources.

(a) Complete the sentences using words from the box.

(i) The panel of solar cells transforms ............................................................................................. energy into electrical energy.

(1)(ii) The wind turbine transforms ............................................................................................. energy into electrical energy.

(1)

(c) The Sankey diagram shows the energy transferred by the panel of solar cells.

Show that the efficiency of the panel of solar cells is 12%.(2)



Q4. A shopping centre has escalators to move people between floors.

(a) A man of mass 78 kg steps on to an escalator.The escalator lifts him a height of 5.0 m.(i) State the equation linking gravitational potential energy, mass, g and height.

(1)

(ii) Show that the gravitational potential energy gained by the man is about 4000 J.

(2)

(c) Another escalator has an efficiency of 20%.Its input energy is 15 kJ.Draw a Sankey diagram for this escalator.

(3)



Q5.

A golfer hits a golf ball and it bounces into the hole.

(a) Use words from the box to complete the sentences below.Each word may be used once, more than once, or not at all.

(i) Each time the golf ball moves upwards, it gains .........................................................................potential energy.

(1)

(ii) Each time the golf ball hits the ground it changes shape and energy is stored as......................................................................... potential energy.

(1)

(iii) When the golf ball is moving it has ......................................................................... energy.

(1)

(b) Each time the ball hits the ground, energy is transferred away from the ball.(i) How can you tell this from the diagram?

(1) .................................................................................................................................

(ii) Describe what happens to the energy that is transferred.(1)

.................................................................................................................................

.................................................................................................................................



Q6. The photograph shows a type of rollercoaster.

The car is launched from point A in the photograph, accelerates to point B and then risesover point C.

(a) Each loaded car has a mass of 2000 kg.C is 128 m above B.

(i) State the equation linking gravitational potential energy, mass, height andgravitational field strength.

(1)

(ii) Show that the gravitational potential energy gained by the car when it rises fromB to C is about 2.6 MJ.

(2)

(b) The car gains kinetic energy when work is done on it by the launching systembetween A and B.

Assume there are no energy losses.(i) State the minimum kinetic energy that the car must have at B for it to reach C.

(1) .................................................................................................................................

(ii) How is the kinetic energy gained related to GPE?(1)

.................................................................................................................................



Fundamentals of Energy

Spec Point Notes

Fundamentals of Energy Spectrum Specification Notes


4.01 use the following units: kilogram (kg), joule (J), metre (m), metre/second (m/s), metre/second2 (m/s2), newton (N), second (s) and watt (W)

4.02 describe energy transfers involving energy stores:• energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic,electrostatic, nuclear• energy transfers: mechanically, electrically, by heating, by radiation(light and sound)

chemical – eg the food we eat

kinetic – movement energy

gravitational – objects that are lifted up

elastic – eg from springs

thermal – from hot objects

magnetic – objects in magnetic fields

electrostatic – charged objects

nuclear – stored within a nucleus

4.03 use the principle of conservation of energy

In any process energy is created or destroyed. (It is just transferred from one store to another.)

4.04 know and use the relationship between efficiency, useful energy output and total energy output:


(×100)

4.05 describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of the above relationship, including their representation by Sankey diagrams


The energy flow is shown by arrows whose width is proportional to the amount of energy involved. The wasted and useful energy outputs are shown by different arrows

4.13 know and use the relationship between gravitational potential energy, mass, gravitational field strength and height:

gravitational potential energy = mass × gravitational field strength × height

GPE = m × g × h

4.14 know and use the relationship:


kinetic energy = 12 x mass x velocity2

KE=12×m×v2

4.15 understand how conservation of energy produces a link between gravitational potential energy, kinetic energy and work


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thequarkyteacher.files.wordpress.com · Web view4.05describe a variety of everyday and scientific devices and situations, explaining the transfer of the input energy in terms of