National 5PhysicsSQAExam QuestionsDynamicsEnergy

Energy (SQA National 5 Physics): Exam Questions

Exam code: X857 75

28 mins8 questions
1
Sme Calculator1 mark

A block is pushed 3.0 m up a slope by a constant force of 6.0 N.

Diagram of a block on a 3.0m inclined plane with a 0.10m height difference. A 6.0N force is applied parallel to the surface, marked "not to scale".

The force of friction between the block and the slope is 2.0 N.

The mass of the block is 1.5 kg.

The work done by the pushing force in moving the block 3.0 m up the slope is

  • 1.5 J

  • 6.0 J

  • 12 J

  • 18 J

  • 24 J

Choose your answer

2
Sme Calculator1 mark

A trolley of mass 4.0 kg is travelling along a track.

The trolley accelerates from 2.0 m s−1 to 6.0 m s−1.

The increase in kinetic energy of the trolley is

  • 32 J

  • 64 J

  • 72 J

  • 80 J

  • 128 J

Choose your answer

3
Sme Calculator6 marks

A seagull flies at a height of 7.5 m above the ground, holding a chip in its beak.

Illustration of a seagull in flight, holding a chip in its beak. The word "chip" is connected to the food item with a line.

The mass of the chip is 0.0025 kg.

(i) Show that the gravitational potential energy of the chip at this height is 0.18 J.

[2]

(ii) The seagull now drops the chip.

Determine the maximum vertical speed of the chip as it reaches the ground.

[3]

(iii) Explain why, in practice, the vertical speed of the chip as it reaches the ground is less than determined in (c) (ii).

[1]

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4
Sme Calculator1 mark

A ball of mass 0.25 kg is released from a height of 6.0 m above the ground.

Diagram showing a ball dropping from a height. The ball falls 4.0 m, depicted with arrows, to a total height of 6.0 m above the ground.

Which row in the table shows the change in gravitational potential energy and the kinetic energy of the ball when it is at a height of 4.0 m above the ground?

Change in gravitational potential energy (J)

Kinetic energy (J)

A

14.7

0.0

B

4.9

4.9

C

9.8

4.9

D

4.9

9.8

E

14.7

14.7

    Choose your answer

    5
    Sme Calculator    4 marks

    The lifeboat has a mass of 25 000 kg. When it is launched, it loses 4·5 cross times105 J of gravitational potential energy before it enters the water.

    Diagram of a boat secured on a slope, held by beams. The boat is drawn in profile, showing structural supports beneath it.

    (i) Calculate the maximum speed of the lifeboat as it enters the water.

    [3]

    (ii) Explain why, in practice, the speed of the lifeboat as it enters the water is less than calculated in (c) (i).

    [1]

    How did you do?

    6
    Sme Calculator    7 marks

    A boardslide is a common trick where a skateboarder uses the middle of the skateboard to slide along a horizontal rail.

    Person skateboards on a rail in a park, performing a trick. Background features trees and graffiti on a wall, captured in black and white.

    The skateboarder and board have a combined mass of 65 kg.

    At the start of the rail, the speed of the skateboarder and board is 7.0 m s-1.

    At the end of the rail, the speed of the skateboarder and board is 3.0 m s-1.

    (i) Determine the decrease in kinetic energy as the skateboarder and board slide along the length of the rail.

    [4]

    (ii) The length of the rail is 2.0 m.

    Calculate the average frictional force between the rail and the skateboard.

    [3]

    How did you do?

    7
    Sme Calculator    1 mark

    A motor is used to apply a force of 120 N to a box of mass 30 kg.

    Diagram of a motor pulling a box with a force of 120 Newtons shown on a flat surface. The motor and box are labelled.

    The box moves at a constant speed across a horizontal surface.

    The box moves a distance of 25 m in a time of 5·0 s.

    Which row in the table shows the work done on the box and the minimum output power of the motor?

    Work done (J)

    Minimum output power (W)

    A

    600

    120

    B

    600

    3000

    C

    3000

    600

    D

    3000

    15 000

    E

    3600

    720

      Choose your answer

      8a
      Sme Calculator      3 marks

      During a BMX competition, a cyclist freewheels down a slope and up a ‘kicker’ to complete a vertical jump.

      Diagram of a BMX rider performing a trick on a half-pipe labelled with "slope" and "kicker"; point "X" marks a specific location on the ramp.

      The cyclist and bike have a combined mass of 75 kg.

      At point X the cyclist and bike have a speed of 8·0 m s−1.

      Calculate the kinetic energy of the cyclist and bike at point X.

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      8b
      Sme Calculator      4 marks

      (i) Calculate the maximum height of the jump above point X.

      [3]

      (ii) Explain why the actual height of the jump above point X would be less than the height calculated in (b) (i).

      [1]

      How did you do?