Lesson T2.2.6

T2.2.6 Stretching springs and Hooke's law Quiz: KS3 Physics, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T2.2.6, Stretching springs and Hooke's law: 20 multiple choice questions for the KS3 Physics (National Curriculum), Unit 2: Motion and forces, written with Revision Ninja.

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The 20 questions

  1. What does Hooke's law say about a stretched spring?

    • The extension of the spring stays the same however large the force applied to it becomes.
    • Extension is inversely proportional to the force applied, so bigger forces give smaller stretches.
    • Force is proportional to the square of the extension at every size of force applied to it.
    • Extension is proportional to force, up to the limit of proportionality.

  2. What is the unit of force used when measuring how far a spring stretches?

    • Joule (J), the SI unit of energy stored when a spring is stretched and released
    • Metre per second (m/s), the SI unit of speed for a moving load on the spring
    • Kilogram (kg), the SI unit of mass used when weighing a load on the spring
    • Newton (N)

  3. What is the extension of a spring?

    • The increase in its length from its original, unloaded length.
    • The mass that must be hung from the end of the spring to stretch it by a set amount.
    • The force needed to stretch the spring by exactly one metre from its unloaded length.
    • The total length of the spring while a load is hanging from it at rest on the bench.

  4. A spring extends by 4 cm under a 2 N force. Staying within its limit of proportionality, what extension would a 6 N force produce?

    • 24 cm, which assumes the extension multiplies by six for every newton applied
    • 8 cm, which assumes the extension doubles only once the force reaches 4 N
    • 6 cm, which assumes the extension rises only by the extra 4 N of force applied
    • 12 cm

  5. A spring stretches 5 cm when a force of 10 N is applied. What is its spring constant?

    • 50 N/m, which divides the force by the extension in centimetres instead of metres
    • 2000 N/m, which divides the force by the extension after converting it wrongly
    • 200 N/m
    • 0.5 N/m, which treats the extension in centimetres as if it were in metres

  6. What happens to a spring that is stretched beyond its limit of proportionality?

    • The extension falls to zero as the force increases further along the force-extension graph.
    • Extension stops rising in direct proportion to force.
    • The spring becomes stronger, so its extension rises faster than the force applied to it.
    • Nothing changes, because Hooke's law applies to every size of force that acts on a spring.

  7. What is the name of the energy stored in a stretched spring?

    • Kinetic energy of the spring as it moves back and forth about its rest position
    • Elastic potential energy
    • Thermal energy that warms the spring as the coils rub together when stretched
    • Chemical energy stored in the metal of the spring by the stretching process

  8. A spring is 10 cm long when unloaded and 14 cm long with a load hung on it. What is its extension?

    • 14 cm, which is the loaded length rather than the change in length of the spring
    • 10 cm, which is the unloaded length of the spring before any load is hung on it
    • 24 cm, which adds the loaded and unloaded lengths together instead of subtracting
    • 4 cm

  9. Which instrument is used to measure the force acting on a spring?

    • A stopwatch, which times how many oscillations the spring completes in one second
    • A voltmeter, which measures the potential difference across a component in a circuit
    • A newtonmeter
    • A thermometer, which is calibrated in degrees Celsius to show the temperature reading

  10. A graph of extension against force for a spring is a straight line through the origin. What does this show?

    • The extension of the spring does not depend on the force applied, so the line should be flat.
    • Force is inversely proportional to extension, so the line should curve downwards from the origin.
    • The spring has stopped obeying Hooke's law, because a straight line through the origin is a warning sign.
    • Extension is directly proportional to force.

  11. Two identical springs each extend 3 cm under a force of 6 N. Within the limit of proportionality, how far does one extend under 12 N?

    • 3 cm, which assumes the extension does not change when the force doubles from 6 N to 12 N
    • 6 cm
    • 9 cm, which assumes the extension rises by 3 cm for every extra 6 N of force applied
    • 18 cm, which assumes the extension multiplies by six when the force is doubled to 12 N

  12. Which expression gives the spring constant of a spring?

    • Extension minus force, which gives the difference between the two readings on the spring
    • Extension divided by force, which gives the flexibility of the spring rather than its stiffness
    • Force divided by extension
    • Force multiplied by extension, which gives the energy stored in the spring when stretched

  13. A constant 5 N force moves its point of application 0.2 m in the direction of the force. How much work is done?

    • 1 J
    • 25 J, which is found by multiplying the force by the distance squared and then by five
    • 5.2 J, which is found by adding the force and the distance together to get the total
    • 0.04 J, which is found by multiplying the force by the square of the distance moved

  14. A spring extends 2 cm under a force of 4 N. Within its limit, what force gives an extension of 7 cm?

    • 8 N, which assumes the force rises by 2 N for each extra centimetre of extension
    • 28 N, which assumes the force is doubled again after the first 2 cm of extension
    • 2 N, which assumes that the force is the same whatever the extension of the spring
    • 14 N

  15. What is the SI unit of the spring constant?

    • Newtons per metre (N/m)
    • Joules per second (J/s), which is the unit of power rather than of spring stiffness
    • Metres per newton (m/N), which is the reciprocal of the unit of the spring constant
    • Newtons per second (N/s), which mixes a force with a rate of change over time

  16. When a stretched spring returns to its original length after the force is removed, the deformation is described as what?

    • Inelastic, because the spring has lost its ability to return to its original length
    • Permanent, because the spring has been changed in shape by the force that acted on it
    • Frictional, because the coils of the spring rubbed against each other during the stretch
    • Elastic

  17. A spring is 12 cm long unloaded. A load produces an extension of 8 cm. What is the new length of the spring?

    • 96 cm, which multiplies the original length by the extension to find the new length
    • 20 cm
    • 8 cm, which is the extension of the spring rather than its new overall length under load
    • 4 cm, which is the difference between the original length and the extension of the spring

  18. A spring extends 3 cm under a force of 1.5 N. What extension would a force of 4.5 N produce, within its limit?

    • 13.5 cm, which adds the original 1.5 N and the extra 3 N of force to the extension
    • 1.5 cm, which assumes the extension is unchanged when the force is increased to 4.5 N
    • 9 cm
    • 4.5 cm, which assumes the extension rises only by the extra 3 N of force applied

  19. Which statement correctly describes Hooke's law?

    • It applies only to liquids and gases that are held inside a sealed container for testing.
    • It is one special case of a linear force-extension relation.
    • It shows that extension grows with the square of the force, so doubling force quadruples extension.
    • It describes how light bends when it crosses a boundary from air into water or glass.

  20. A student plots force against extension for a spring and the points curve away from a straight line after a certain force. What has most likely happened?

    • The force has been measured in joules instead of newtons, so the points no longer line up on the graph.
    • The spring has been stretched less than its original length, so the points curve back towards the origin.
    • The spring has become a conductor of electricity, which changes how it stretches under load.
    • The spring has been stretched beyond its limit of proportionality.

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