Syllabus Edition

First teaching 2023

First exams 2025

|

Energy Conservation (CIE AS Physics)

Exam Questions

3 hours45 questions
1
Sme Calculator
1 mark

Which of the following is a statement of the principle of conservation of energy?

  • energy is the product of force and distance

  • energy cannot be created, destroyed or transformed

  • the total energy of an isolated system is constant

  • the power transmitted by a system is proportional to the rate of transfer of energy 

Did this page help you?

2
Sme Calculator
1 mark

Which expression defines power?

  • force × displacement in the direction of the force

  • force × velocity

  • work done ÷ time taken

  • work done × time taken

Did this page help you?

3
Sme Calculator
1 mark

The total energy input Ein in a process is partly transferred to useful energy output U, and partly to energy that is wasted W

 What is the efficiency of the process?

  • U over W cross times 100 percent sign

  • W over E subscript i n end subscript cross times 100 percent sign

  • U over E subscript i n end subscript cross times 100 percent sign

  • fraction numerator U plus W over denominator E subscript i n end subscript end fraction cross times 100 percent sign

Did this page help you?

4
Sme Calculator
1 mark

A boat moving at constant speed v through still water experiences a total frictional drag F

 What is the power developed by the boat?

  • 1 half F v

  • F v

  • 1 half F v squared

  • F v squared

Did this page help you?

5
Sme Calculator
1 mark

What is the average power output of a laser that can deliver 0.20 J of energy in 10 ns?

  • 2 nW

  • 20 mW

  • 200 kW

  • 20 MW

Did this page help you?

6
Sme Calculator
1 mark

A transformer has the following input and output 

 

Potential difference / V

Current / A

Input

Output

11 000

240

28

1200


What is the efficiency of the transformer?

  • 0.94 %

  • 1.0 %

  • 11 %

  • 94 %

Did this page help you?

7
Sme Calculator
1 mark

Which operation involves the greatest mean power?

  • a car moving against a resistive force of 0.4 kN at a constant speed of 20 m s–1

  • a crane lifting a weight of 3 kN at a speed of 2 m s–1

  • a crane lifting a weight of 5 kN at a speed of 1 m s–1

  • a weight being pulled across a horizontal surface at a speed of 6 m s–1 against a frictional force of 1.5 kN

Did this page help you?

8
Sme Calculator
1 mark

An electric motor is required to produce 120 W of mechanical output power. The efficiency of the motor is 80%

Which row is correct?

 

Electrical power input to motor
/ W

Waste heat output from motor
/ W

A

120

24

B

120

96

C

150

30

D

150

120

    Did this page help you?

    9
    Sme Calculator
    1 mark

    When bungee jumping, a student starts with maximum gravitational potential energy (position 1), then falls freely until the rope fully unwinds (position 2), after which the rope starts to stretch until the lowest point of the jump is reached (position 3)

    cie-ial-images204png

    What are the kinetic and elastic potential energies at position 3?

     

    Kinetic energy

    Elastic potential energy

    A

    maximum

    maximum

    B

    maximum

    minimum

    C

    minimum

    maximum

    D

    minimum

    minimum

      Did this page help you?

      10
      Sme Calculator
      1 mark

      The kinetic energy of a moving vehicle with mass 1000 kg is 4.5 × 105 J. It brakes with a total constant braking force of 6000 N

       What will be its stopping distance?

      • 37 m

      • 75 m

      • 150 m

      • 300 m

      Did this page help you?

      1
      Sme Calculator
      1 mark

      The diagram shows a pump called a hydraulic ram

      cie-ial-images205png

      In one such pump the long approach pipe holds 500 kg of water. A valve shuts when the speed of this water reaches 2.0 m s–1 and the kinetic energy of this water is used to lift a small quantity of water by a height of 15 m.

       The efficiency of the pump is 10 %.

      Which mass of water could be lifted 15 m?

      • 0.15 kg

      • 0.68 kg

      • 1.5 kg

      • 6.8 kg

      Did this page help you?

      2
      Sme Calculator
      1 mark

      Trains supply coal to a power station. The table below gives quantities describing the operation of the power station.

       

       

      Symbol

      Unit

      power station output

      P

      W

      number of trains per day

      N

       

      mass of coal on a train

      M

      kg

      energy from 1 kg of coal

      J

      J

      number of seconds in one day

      S

      s

        

      Which expression gives efficiency of the power station?

      • fraction numerator P S over denominator N M J end fraction

      • fraction numerator P S N over denominator M J end fraction

      • fraction numerator N M J over denominator P S end fraction

      • fraction numerator N M over denominator P S J end fraction

      Did this page help you?

      3
      Sme Calculator
      1 mark

      Water flows from a lake into a turbine that is a vertical distance of 90 m below the lake, as shown

      cie-ial-images206png

      The mass flow rate of the water is 2400 kg min–1. The turbine has an efficiency of 75 %.

       What is the output power of the turbine?

      • 26 kW

      • 35 kW

      • 1.6 MW

      • 2.1 MW

      Did this page help you?

      4
      Sme Calculator
      1 mark

      Initially, four identical uniform blocks, each of mass m and thickness h, are spread on a table.

       cie-ial-images207png

       

      How much work is done on the blocks in stacking them on top of one another?

      • 3 space m g h

      • m g h

      • m g h

      • 10 m g h

      Did this page help you?

      5
      Sme Calculator
      1 mark

      The first column in the table gives four examples of work being done. The second column gives more detail of the action.

       Which row is not correct?

       

      Example

      Detail

      A

      a girl dives from a diving board into a swimming pool

      work is done by the girl against gravity as she falls

      B

      a man pushes a car along a level road

      work is done by the man against friction

      C

      an electron is accelerated towards a positively-charged plate

      work is done on the electron by the electric field of the plate

      D

      a piston is pushed outwards as a gas expands

      work is done on the atmosphere by the gas

        Did this page help you?

        6
        Sme Calculator
        1 mark

        The data below are taken from a test of a petrol engine for a motor car.

        power output

        150 kW

        fuel consumption

        20 litres per hour

        energy content of fuel

        40 MJ per litre

         
        Which expression will evaluate the efficiency of the engine?

        • fraction numerator 150 cross times 10 cubed over denominator 40 cross times 10 to the power of 6 cross times 20 cross times 60 cross times 60 end fraction

        • fraction numerator 150 cross times 10 cubed cross times 60 cross times 60 over denominator 20 cross times 40 cross times 10 to the power of 6 end fraction

        • fraction numerator 150 cross times 10 to the power of 3 cross times end exponent 40 cross times 10 to the power of 6 cross times 20 over denominator 60 cross times 60 end fraction

        • fraction numerator 150 cross times 10 cubed cross times 20 over denominator 40 cross times 10 to the power of 6 cross times 60 cross times 60 end fraction

        Did this page help you?

        7
        Sme Calculator
        1 mark

        A constant force F, acting on a car of mass m, moves the car up a slope through a distance s at constant velocity v. The angle of the slope to the horizontal is α.

        cie-ial-images209png

        Which expression gives the efficiency of the process?

        • fraction numerator m g s space sin space alpha over denominator F v end fraction

        • fraction numerator m v over denominator F s end fraction

        • fraction numerator m v squared over denominator 2 F s end fraction

        • fraction numerator m g space sin space alpha over denominator F end fraction

        Did this page help you?

        8
        Sme Calculator
        1 mark

        A weight W hangs from a trolley that runs along a rail. The trolley moves horizontally through a distance p and simultaneously raises the weight through a height q

        cie-ial-images210png

        As a result, the weight moves through a distance r from X to Y. It starts and finishes at rest.

         How much work is done on the weight during this process?

        • Wp

        • W(p + q)

        • Wq

        • Wr

        Did this page help you?

        9
        Sme Calculator
        1 mark

        A bungee jumper has 24 kJ of gravitational potential energy at the top of his jump. He is attached to an elastic rope which starts to stretch after a short time of free fall. Assume that energy loss through air resistance is negligible.

         

         

        GPE / kJ

        EPE / kJ

        KE / kJ

        Top

        24

        0

        0

        Bottom

        0

        24

        0

         

        What are the possible values when the jumper is half-way down?

         

         

        GPE / kJ

        EPE / kJ

        KE / kJ

        A

        12

        10

        2

        B

        12

        8

        4

        C

        8

        8

        8

        D

        12

        2

        10

          Did this page help you?

          10
          Sme Calculator
          1 mark

          The diagram shows the design of a water wheel which drives a generator to produce electrical energy. The flow rate of the water is 200 kg s–1. The generator supplies a current of 32 A at a voltage of 230 V.

          cie-ial-images212png

          Ignoring any changes in kinetic energy of the water, what is the efficiency of the system?

          • 14 %

          • 16 %

          • 22 %

          • 47 %

          Did this page help you?

          11
          Sme Calculator
          1 mark

          A conveyor belt is driven at velocity V by a motor. Sand drops vertically on to the belt at a rate of straight m space kg space straight s to the power of negative 1 end exponent.

          What is the additional power needed to keep the conveyor belt moving at a steady speed when the sand starts to fall on it ?

          • 1 half m v

          • m v

          • 1 half m v squared

          • m v squared

          Did this page help you?

          12
          Sme Calculator
          1 mark

          The force resisting the motion of a car is taken as being proportional to the square of the car's speed. The magnitude of the force at a speed of 20 space straight m space straight s to the power of negative 1 end exponent is 800 N.

          What effective power is required from the car's engine to maintain a steady speed of 40 space straight m space straight s to the power of negative 1 end exponent?

          • 32 kW

          • 64 kW

          • 128 kW

          • 512 kW

          Did this page help you?

          13
          Sme Calculator
          1 mark

          A mass is raised vertically. In a time t, the increase in its gravitational potential energy is E subscript p and the increase i its kinetic energy is E subscript k.

          what is the average power input to the mass?

          • open parentheses E subscript p minus E subscript k close parentheses t

          • open parentheses E subscript p plus E subscript K close parentheses t

          • fraction numerator E subscript p minus E subscript k over denominator t end fraction

          • fraction numerator E subscript p plus E subscript k over denominator t end fraction

          Did this page help you?

          1
          Sme Calculator
          1 mark

          A turbine at a hydroelectric power station is situated 30 m below the level of the surface of a large lake. The water passes through the turbine at a rate of 340 m3 per minute.

           The overall efficiency of the turbine and generator system is 90 %.

           What is the output power of the power station? (The density of water is 1000 kg m–3)

          • 0.15 MW

          • 1.5 MW

          • 1.7 MW

          • 90 MW

          Did this page help you?

          2
          Sme Calculator
          1 mark

          A small mass is placed at point P on the inside surface of a smooth hemisphere. It is then released from rest. When it reaches the lowest point T, its speed is 4.0 m s–1.

          The diagram (not to scale) shows the speed of the mass at other points Q, R and S as it slides down. Air resistance is negligible.

          5-1-q22

          The mass loses potential energy E in falling from P to T.

          At which point has the mass lost potential energy  E over 4 ?

          • Q

          • R

          • S

          • none of these

          Did this page help you?

          3
          Sme Calculator
          1 mark

          An escalator is 60 m long and lifts passengers through a vertical height of 30 m, as shown.

           cie-ial-images213png

          To drive the escalator against the forces of friction when there are no passengers requires a power of 2.0 kW.

          The escalator is used by passengers of average mass 60 kg and the power to overcome friction remains constant.

           How much power is required to drive the escalator when it is carrying 20 passengers and is travelling at 0.75 m s–1?

          • 4.4 kW

          • 6.4 kW

          • 8.8 kW

          • 10.8 kW

          Did this page help you?

          4
          Sme Calculator
          1 mark

          A wind turbine has blades that sweep an area of 2000 m2. It converts the power available in the wind to electrical power with an efficiency of 50 %.

           What is the electrical power generated if the wind speed is 10 m s–1? (The density of air is 1.3 kg m–3)

          • 130 kW

          • 650 kW

          • 1300 kW

          • 2600 kW

          Did this page help you?

          5
          Sme Calculator
          1 mark

          The figure shows a mass m on an inclined plane connected by an inextensible string over a smooth pulley to a larger mass M. When the mass M falls through a distance x, the mass m moves up a vertical distance y at a constant speed.

           The friction between m and the inclined plane is F.

          cie-ial-images214png

          What amount of energy is converted to heat?

          • F space open parentheses space x minus y space close parentheses

          • F y

          • M g x minus m g y

          • open parentheses M minus m close parentheses space g x

          Did this page help you?

          6
          Sme Calculator
          1 mark

          The diagram shows a wheel of circumference 0.30 m. A rope is fastened at one end to a force meter. The rope passes over the wheel and supports a freely hanging load of 100 N. The wheel is driven by an electric motor at a constant rate of 50 revolutions per second.

           When the wheel is turning at this rate, the force meter reads 20 N.

          cie-ial-physics-mcq-5-1-q26

          What is the output power of the motor?

          • 0.3 kW

          • 1.2 kW

          • 1.8 kW

          • 3.8 kW

          Did this page help you?

          7
          Sme Calculator
          1 mark

          The figure below shows two blocks P and Q, initially stationary and connected to each other by a taut string passing over a smooth pulley. The system is released from rest and block Q moves vertically downwards from position A to B.

          cie-ial-physics-mcq-5-1-q27

          Which of the following statements is correct?

          • Potential energy of the block Q at A = Kinetic energy of block Q at B

          • Loss in potential energy of the whole system = Gain in kinetic energy of the whole system + work done against friction due to block P moving against a rough surface

          • Loss in potential energy of the whole system = Gain in kinetic energy of the system

          • Loss in potential energy of block Q = Gain in potential energy of block P

          Did this page help you?

          8
          Sme Calculator
          1 mark

          A boy on a boat P pulls on a rope with a constant force F over a duration of time t. The other end of the rope is either tied to an anchor on the pier (Diagram a) or a freely floating boat Q (Diagram b) of equal mass as shown in the figures shown.

          cie-ial-images218png

          Wa and Wb represent the total work done by the boy during the time t and Pa and Pb represent the average power output of the boy in diagrams (a) and (b) respectively.

           Which of the following statements is correct?

          •  W subscript a greater than W subscript b space a n d space P subscript a space end subscript greater than P subscript b

          • W subscript a equals W subscript b space a n d space P subscript a equals P subscript b

          • W subscript a less than W subscript b space a n d space P subscript a space end subscript less than space P subscript b

          • W subscript a less than W subscript b space a n d space P subscript a equals P subscript b

          Did this page help you?

          9
          Sme Calculator
          1 mark

          What is the power required to give a body of mass m a forward acceleration a when it is moving with velocity v up a frictionless track inclined at an angle θ to the horizontal?

          • m a v g space sin space theta

          • m a v space sin space theta plus m g v

          • m a v space plus m g v space sin space theta

          • open parentheses m a v plus m g v close parentheses sin space theta

          Did this page help you?

          10
          Sme Calculator
          1 mark

          A ball of mass m falls freely from rest. When it has reached a speed v, it strikes a vertical spring.

           The spring is compressed by a distance y before the ball moves upwards again.

          cie-ial-images219png

          Assume that all energy the ball loses becomes elastic potential energy in the spring.

           What is the average force exerted by the spring during its compression?

          • fraction numerator m v squared over denominator 2 y end fraction

          • fraction numerator m over denominator 2 y end fraction open parentheses v squared minus 2 g y close parentheses

          • fraction numerator m v squared over denominator y end fraction

          • fraction numerator m over denominator 2 y end fraction open parentheses v squared plus 2 g y close parentheses

          Did this page help you?