Driven Oscillations, Resonance and the Quality Factor · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Pushing at the favourite frequency

Science · Forces & Motion · ages 19-20
Name ______________________   Date ____________

  1. How does light damping change the resonance curve?

    • It erases the peak entirely
    • It gives a tall narrow spike near resonance
    • It widens the peak and shortens all motion

  2. What does steady amplitude against driving frequency look like?

    • Small far off, soaring where the frequencies match
    • Flat at all driving frequencies
    • Largest at zero driving frequency

  3. What does a high quality factor tell you?

    • Broad peak with quick dying
    • No resonance at any frequency
    • Sharp peak with long lasting free swings

  4. Which pairs a wanted with an unwanted case of resonance?

    • Musical instruments with bridges that must avoid it
    • Bridges with engines that want more of it
    • Radio tuners with instruments that avoid it

  5. How do you drive an oscillator to large amplitude?

    • Push at random moments
    • Drive it at its natural frequency with timed pushes
    • Hold it still at the peak

  6. A lightly damped system has both a tall resonance peak and a long ring-down.

    Circle one:   True   False

  7. Resonance needs zero damping to appear at all.

    Circle one:   True   False

  8. A footbridge hums near its natural frequency under marching feet. What is the safe fix?

    • Drive it harder at the peak to push through
    • Add damping to spoil the peak
    • Remove all damping so it rings freely
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Pushing at the favourite frequency W1-mt_FmpOTEZFy4-s1

  1. It gives a tall narrow spike near resonance · Little damping lets the peak grow tall and sharp.
  2. Small far off, soaring where the frequencies match · The curve peaks where the push matches the system.
  3. Sharp peak with long lasting free swings · High Q pairs pickiness with slow energy loss.
  4. Musical instruments with bridges that must avoid it · Instruments are built to sing; bridges are damped to survive.
  5. Drive it at its natural frequency with timed pushes · Each cycle then adds energy in step with the motion.
  6. True · Weak damping caps little and drains slowly.
  7. False · Peaks appear with damping too; light damping just makes them taller.
  8. Add damping to spoil the peak · Extra damping caps the peak and drains the motion.
Worksheet · LightMySky