High Demand Questions                            QUESTIONSHEET 1

(a) A weightlifter lifts a mass of 50 kg to a height of 2.5 m.

Calculate the work done by the weightlifter.

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                      ..................................................................................................................................................................                (3)

(b) The table shows the maximum weights lifted by three weightlifters.

 weightlifter Maximum mass (kg) Distance (m) Work done (J) John 65 2.5 1625 Mike 70 2.5 Alan 50 2.4 1200 Jeff 75 2.0

(i)    Calculate and fill in the missing quantities.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (2)

(ii)    Who lifted the heaviest mass ?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(iii)   Who did the most work ?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(c) What mass in kg must Jeff lift to do the same amount of work as Mike ?

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............................................................................................................................................................ [4]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (4)

TOTAL  / 11

High Demand Questions                            QUESTIONSHEET 2

(a) Carl and James are climbing a hill of height 500 m.

Carl is slow, so James goes on ahead.

The weights of three people and their times to climb the hill are shown in the table below:

 Carl James Victoria weight (N) 650 800 500 time (s) 5000 3000 2000

Calculate the work done by Carl in climbing the hill.

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(b) Victoria is a fell runner.  She overtakes Carl and James.

Use the equation:

Power  =  work done

time

to calculate the power in Victoria’s muscles.

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                (3)

(c) What is the difference in muscular power between Victoria and Carl ?

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............................................................................................................................................................ [4]                                                                                                                                                                                     ..................................................................................................................................................................                     (4)

TOTAL  / 10

High Demand Questions                            QUESTIONSHEET 3

(a) A boulder is balanced at the top of a cliff of height 45 m.  The boulder weighs 1 kN.

The boulder falls to the ground at the base of the cliff.

(i)    What happens to its potential energy as it falls ?

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............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (1)

(ii)    Use the equation:

potential energy  =  force  ´  vertical distance

to calculate the potential energy of the boulder.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (2)

(b) Use the equation:

kinetic energy  =  ½  ´  mass  ´  velocity2

to calculate the velocity with which the boulder hits the ground. (Take g = 10 ms-2)

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(c) How much work would have to be done to raise the boulder back to the top of the cliff ?

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TOTAL  / 9

High Demand Questions                            QUESTIONSHEET 4

(a) A horse is pulling a cart up a hill as shown in the diagram. The horse and cart together weigh 120 N.

 1200 n

 5m

Calculate the work done by the horse in pulling the cart from the bottom of the hill to the top.

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(b) Use the equation:

potential energy  =  force  ´  vertical distance

to calculate the potential energy of the cart at the top of the hill.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                     (2)

(c) (i)    Use the equation:

efficiency  =  useful energy output   ´  100

total energy input

to calculate the efficiency of the horse.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                     (2)

(ii)    Why is the efficiency of the horse not 100% ?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(iii)   How could this be improved ?

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TOTAL  / 8

High Demand Questions                            QUESTIONSHEET 5

The table shows power ratings and heat losses for three types of light bulb.

 bulb energy efficient standard fluorescent strip power rating (W) 20 100 20 power lost as heat (W) 1 80 8 efficiency (%)

(a) Use the equation:

efficiency  =  useful energy output  ´  100

total energy input

to calculate the efficiency of each bulb.  Write your answers in the table.

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(b) (i)    Which type of bulb is the least efficient ?

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(ii)    Where does the wasted energy go ?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                (1)

(c) Give two reasons why energy efficient bulbs are considered to be better for the environment

than standard bulbs.

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TOTAL  / 10

High Demand Questions                            QUESTIONSHEET 6

An engine is shunting some wagons in a marshalling yard.

Each wagon weighs 5 tonnes.

One wagon is pushed at a speed of 3 m/s into four others.

The wagons couple together.

(a) What was the kinetic energy of the first wagon just before it hit the other four?

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(b) What is the speed of the five coupled wagons?

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(c) What is the total kinetic energy of the five wagons?

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(d) (i)      How much kinetic energy has been lost?

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(ii)     Where has this kinetic energy gone?

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TOTAL  / 10

High Demand Questions                            QUESTIONSHEET 7

A man was rescued from a cliff by a helicopter.  The man weighed 80 kg.

The helicopter has to lift the man 30 m.

(g = 10 N/kg)

(a) What is the SI unit of power?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(b) What is the relationship between the number of joules and the power?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(c) Calculate the potential energy the man gains as he is lifted.

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                     (3)

(d) What power must the helicopter supply if lifting the man takes 15 s?

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TOTAL  / 8

High Demand Questions                            QUESTIONSHEET 8

Nina is a very versatile sportswoman.

Her mass is 55 kg. Take the acceleration due to gravity as 10 m/s-2.

(a) If g = 10 N/kg, what is Nina’s weight?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(b) (i)    Nina competes in a pole vault event.  She jumps 3.5 m.

Calculate her gravitational potential energy when she is at her highest point.

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                     (3)

(ii)     What is her kinetic energy just before she lands?

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(c) Later she throws a rounders ball vertically upwards at 12 m/s.

How high does it go?

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............................................................................................................................................................ [4]                                                                                                                                                                                     ..................................................................................................................................................................                     (4)

(d) In training, Nina can do 900 J of work in 5 seconds.

How much power does she produce?

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TOTAL  / 11

Medium Demand Questions                       QUESTIONSHEET 9

(a) A porter carries a suitcase weighing 30 kg upstairs in a hotel.

The height of the first floor is 3m above the ground.

Using the equation:

Potential energy  =  force  ´  vertical height

calculate the potential energy gained by the case from the ground floor to the top of the stairs.

(2)

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(b) Another porter took the lift with a suitcase of the same mass.

How much potential energy does the second suitcase gain ?

(1)

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(c) Explain where the energy comes from in each situation.

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TOTAL  / 5

Medium Demand Questions                      QUESTIONSHEET 10

The table shows some power ratings of some household appliances.

 appliance kettle light bulb iron hair drier power rating (W) 2000 100 2500 700

(a) Use the equation:

power  =  energy transferred

time

to calculate the energy used in the following:

(i)    a kettle used for 5 minutes

(1)

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(ii)    a light bulb, which is on for 10 hours

(1)

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(b) On Monday, the iron was used for 10 minutes.

How long would the light bulb have to be on to use the same amount of energy ?

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                     (3)

(c) Electrical energy is used to power appliances.

State the energy conversions taking place in the following:

(i)    an iron

(1)

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(ii)    a light bulb

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(iii)   a hair drier

(1)

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TOTAL  / 8

Medium Demand Questions                      QUESTIONSHEET 11

(a) A squash ball is dropped to the ground.

State the energy changes taking place:

(i)   as it falls towards the ground

(1)

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(ii)    as it hits the ground

(1)

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(iii)   as it bounces upwards

(1)

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(b) (i)    Use the equation:

potential energy  =  force  ´  vertical distance

to calculate the potential energy of a squash ball of mass 30 g, held at a height of 1.8 m.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (2)

(ii)      Use the equation:

kinetic energy  =  ½  ´  mass  ´  velocity2

to calculate the velocity of the ball as it hits the ground after being dropped.

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TOTAL  / 9

Medium Demand Questions                      QUESTIONSHEET 12

The table shows the results of a class experiment to measure the power developed in the legs when running upstairs. The staircase is of height 4 metres.

 Weight (N) Time to climb (s) Power developed in legs (W) Megan 400 5 320 Lucy 430 4 Anouja 350 7 200 Carol 450 6

(a)Use the equation:

power  =  work done

time taken

to calculate the power developed in the legs of Lucy and Carol.

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(b) Whose legs were the most powerful ?

(1)

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(c) Where does the energy come from ?

(1)

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(d) If they all took the same time to climb the stairs, who would develop the most power in their legs?

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TOTAL  / 7

Medium Demand Questions                      QUESTIONSHEET 13

A wind farm was set up on top of a hill in the Pennines.

Energy from the wind is described as ‘renewable’.

(a) What is meant by a renewable energy source ?

(1)

............................................................................................................................................................ [1]

(b) (i)    A wind generator typically supplies 5 MW of power.

How many wind generators would be needed to supply the same power as a 1000 MW power station ?

(1)

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(ii)   Why would more be needed in practice ?

(1)

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(c) The table below shows the length of time during each of five days when there was enough wind to

turn the turbines.

 day 1 2 3 4 5 minutes of wind 300 0 1200 600 1200

(i)    Use the equation:

power  =  energy transferred

time

to calculate the energy output of one turbine for these five days.

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(ii)    If the system is 50 % efficient, how much energy is actually generated in the five days ?

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TOTAL  / 7

Medium Demand Questions                      QUESTIONSHEET 14

Energy transferred  =  force  ´  distance moved by force

The unit of energy could be expressed as Nm.

(a) What other name is given to the unit of energy?

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(b) (i)    A can of beans, having a mass of 0.3 kg, was picked up and lifted 0.5 m to a shelf.

How much energy is transferred? (Take g = 10 ms-2)

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............................................................................................................................................................ [3]                                                                                                                                                                                     ..................................................................................................................................................................                     (3)

(ii)   The can falls off the shelf and hits the floor.

How much energy is transferred as the can falls?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(iii)   What is the weight of the can?

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TOTAL  / 7

Medium Demand Questions                      QUESTIONSHEET 15

(a) (i)    What is meant by an elastic collision?

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(ii)  Why are most collisions non-elastic?

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(b) Name and explain two features of a modern car which are designed to make it safe.

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(c) A man driving a car of mass 200 kg exerts a force on the brake to stop from a speed of 15 m/s.

It takes the car 30 m to stop.

(i)  What is the kinetic energy of the car just before braking?

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(ii)  What is the average force acting on the brakes of the car?

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TOTAL  / 13

Medium Demand Questions                      QUESTIONSHEET 16

A group of students carried out three experiments on energy changers.

(a) In the first experiment, Gareth connected an electric motor to a battery and used it lift a load of 3 N.

It took 10 s to lift it 1 metre.

(i)   Write down the energy changes which take place

(3)

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(ii)    Calculate the work done in lifting the load.

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(iii)   Calculate the power of the motor.

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(b) Laura then used a falling mass of 10N to turn a dynamo and light a lamp.

The load fell at a constant speed of 2 m/s.

(i)    Write down the energy changes which take place.

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(ii)   Calculate the kinetic energy of the load just before it stops falling.

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(c) Yvonne decided to use a steam engine to lift a 5N load.

Write down the energy changes which take place.

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TOTAL  / 17

Low Demand Questions                                         QUESTIONSHEET 17

A kitchen is a room full of energy changers, most of which are powered by electrical energy.

Complete the changes for the following pieces of equipment.

(a)Cooker                  electrical  à   _______  and  __________                                                               [2]                         (2)

(b)Mobile phone         _______  à  electrical  à  ____________                                                              [2]                           (2)

(c)Clock                    electrical  à  _______  and  ___________                                                              [2]                         (2)

(d)light bulb                electrical  à  _______  and  ___________                                                              [2]                         (2)

TOTAL  / 8

Low Demand Questions                           QUESTIONSHEET 18

(a) List the names of six different forms of energy.

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(b) Complete the following sentences:

(i)    One joule of work is done when a force of one ________________ moves a

distance of one ________________.                                                                                             [2]                             (2)

(ii)    The principle of _________________ of energy says that energy can be ___________

from one form to another, but that it cannot be _____________ or __________________.            [4]                                                                                                                                                                                (4)

TOTAL  / 12

Low Demand Questions                           QUESTIONSHEET 19

(a) The table below shows the percentage of funds spent on energy research going into different areas.

 research area % of total spent energy efficiency 6 coal, oil, gas 10 renewable sources 11 Nuclear fusion 27 nuclear energy 57

Why would someone concerned about the environment be unhappy with these figures?

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(b) A number of sources of energy are mentioned in the table.

Why isn’t electricity one of them?

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(c) Which of the energy sources are likely to run out in your lifetime?

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TOTAL  / 6

Low Demand Questions                           QUESTIONSHEET 20

(a) Most of the World’s energy supply come from one source.

(i)     What is that source?

............................................................................................................................................................ [1]                                                                                                                                                                                     ..................................................................................................................................................................                     (1)

(ii)    Explain how the energy from that source gets into potatoes.

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............................................................................................................................................................ [2]                                                                                                                                                                                     ..................................................................................................................................................................                                                                                                                                                                                 ............................................................................................................................................................ (2)

(iii)   Explain how the energy from that source gets into coal.

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(b) A pendulum is used as an energy changer.

(i)    at which position does the pendulum have the largest potential energy?

(1)

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(ii)    at which position does the pendulum have the largest kinetic energy?

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TOTAL  / 8