Resonance in Vibrating Systems Knowledge Assessment

1. Resonance happens when:

A system is not moving

A system is driven at (or near) its natural frequency

A system’s mass becomes zero

A wave travels faster than light

Resonance occurs when the driving frequency matches the system’s natural frequency, so energy transfer is very efficient. This often produces a large steady amplitude.

Explanation

Resonance occurs when the driving frequency matches the system’s natural frequency, so energy transfer is very efficient. This often produces a large steady amplitude.

2. A swing goes higher if you push it at the right timing repeatedly.

True

False

Pushing in sync with the swing adds energy each cycle. This is resonance: repeated efficient energy input builds amplitude.

Explanation

Pushing in sync with the swing adds energy each cycle. This is resonance: repeated efficient energy input builds amplitude.

3. The natural frequency of a system is:

The loudness of the system

The frequency the system prefers to oscillate at when disturbed

The system’s temperature

The system’s weight

If you displace a system and let it go, it tends to oscillate at its natural frequency. This frequency depends on physical properties like length, stiffness, and mass.

Explanation

If you displace a system and let it go, it tends to oscillate at its natural frequency. This frequency depends on physical properties like length, stiffness, and mass.

4. A periodic push or force applied to an oscillator is called a ______ force.

A driving force supplies energy from outside the system. Resonance occurs when its frequency matches the system’s natural frequency.

Explanation

A driving force supplies energy from outside the system. Resonance occurs when its frequency matches the system’s natural frequency.

Submit

5. When the driving frequency is far from the natural frequency, the steady amplitude is usually:

Maximum

Small

Infinite

Negative

Energy transfer is inefficient when the timing doesn’t match. The oscillator still responds, but with a smaller amplitude.

Explanation

Energy transfer is inefficient when the timing doesn’t match. The oscillator still responds, but with a smaller amplitude.

6. Damping tends to reduce the amplitude of oscillations.

True

False

Damping removes energy from the system (often as heat). This reduces amplitude and makes oscillations die out unless driven.

Explanation

Damping removes energy from the system (often as heat). This reduces amplitude and makes oscillations die out unless driven.

7. Which is an example of damping?

A perfectly frictionless swing

Air resistance slowing a moving pendulum

A perfectly rigid wall

A constant temperature

Damping includes friction, air resistance, and internal material losses. These reduce motion by dissipating energy.

Explanation

Damping includes friction, air resistance, and internal material losses. These reduce motion by dissipating energy.

8. At resonance, the amplitude is large mainly because:

The system stops losing energy

Energy is added each cycle in phase with the motion

Gravity becomes stronger

Frequency becomes zero

When the drive is in sync, each push adds energy at the right moment. This builds amplitude until damping balances the input.

Explanation

When the drive is in sync, each push adds energy at the right moment. This builds amplitude until damping balances the input.

9. Even at resonance, amplitude does not grow forever in real systems.

True

False

Real systems lose energy to damping and have material limits. Amplitude reaches a steady value when energy in per cycle equals energy lost.

Explanation

Real systems lose energy to damping and have material limits. Amplitude reaches a steady value when energy in per cycle equals energy lost.

10. The loud sound from blowing across a bottle is an example of:

Diffraction

Refraction

Resonance of the air column

Polarisation

The air inside the bottle has natural modes of vibration. Blowing excites one mode strongly, producing a tone.

Explanation

The air inside the bottle has natural modes of vibration. Blowing excites one mode strongly, producing a tone.

11. The maximum response of a driven oscillator typically occurs near the ______ frequency.

The response curve peaks when the driving frequency matches the system’s natural frequency. This is the resonance condition.

Explanation

The response curve peaks when the driving frequency matches the system’s natural frequency. This is the resonance condition.

Submit

12. Increasing damping usually makes the resonance peak less sharp (broader and lower).

True

False

More damping removes energy more quickly. This reduces maximum amplitude and spreads the response over a wider range of frequencies.

Explanation

More damping removes energy more quickly. This reduces maximum amplitude and spreads the response over a wider range of frequencies.

13. Which change is most likely to change a pendulum’s natural frequency?

Changing its colour

Changing its length

Changing the room lighting

Changing the pendulum’s name

For a pendulum, length strongly affects how quickly it swings. Physical parameters determine natural frequency, not cosmetic details.

Explanation

For a pendulum, length strongly affects how quickly it swings. Physical parameters determine natural frequency, not cosmetic details.

14. Resonance is useful in musical instruments because it:

Makes sound quieter

Amplifies certain frequencies

Removes pitch

Stops vibrations instantly

Instruments use resonant bodies or air columns to boost sound at particular frequencies. This increases loudness and shapes tone quality.

Explanation

Instruments use resonant bodies or air columns to boost sound at particular frequencies. This increases loudness and shapes tone quality.

15. If you drive an oscillator at its natural frequency, the phase relationship between drive and motion tends to make energy transfer efficient.

True

False

The timing of the driving force relative to motion matters. At resonance, the system responds in a way that allows strong energy transfer.

Explanation

The timing of the driving force relative to motion matters. At resonance, the system responds in a way that allows strong energy transfer.

16. A playground swing is easiest to push higher when you push:

Randomly

Twice as fast as the swing moves

With the same period as the swing

Only at the highest point

Pushing once per cycle in the right direction adds energy efficiently. This corresponds to matching the swing’s natural period.

Explanation

Pushing once per cycle in the right direction adds energy efficiently. This corresponds to matching the swing’s natural period.

17. Resonance can be dangerous in structures if vibrations build to large amplitudes.

True

False

If a driving frequency matches a structure’s natural frequency, amplitude can grow large. This can cause fatigue or even failure.

Explanation

If a driving frequency matches a structure’s natural frequency, amplitude can grow large. This can cause fatigue or even failure.

18. The frequency range over which resonance is strong is related to the system’s ______ (energy losses).

Damping controls selectivity. Low damping gives a sharp, narrow resonance peak. High damping spreads the response and reduces the peak amplitude.

Explanation

Damping controls selectivity. Low damping gives a sharp, narrow resonance peak. High damping spreads the response and reduces the peak amplitude.

Submit

19. Which is most likely to have a sharp resonance peak?

A heavily damped shock absorber

A lightly damped tuning fork

A sponge in water

A loose pile of sand

Light damping gives sharp resonance. Tuning forks lose energy slowly, so they have a clear natural frequency and strong resonance. Heavy damping smears out the response.

Explanation

Light damping gives sharp resonance. Tuning forks lose energy slowly, so they have a clear natural frequency and strong resonance. Heavy damping smears out the response.

20. Resonance is not a special force; it is a response effect caused by matching frequencies and efficient energy transfer.

True

False

Resonance comes from how oscillators store and exchange energy. Matching the drive frequency lets energy accumulate efficiently.

Explanation

Resonance comes from how oscillators store and exchange energy. Matching the drive frequency lets energy accumulate efficiently.

Resonance Quiz: Test Your Knowledge Of Vibrating Systems

1. Resonance happens when:

2.

What first name or nickname would you like us to use?

2. A swing goes higher if you push it at the right timing repeatedly.

3. The natural frequency of a system is:

4. A periodic push or force applied to an oscillator is called a ______ force.

5. When the driving frequency is far from the natural frequency, the steady amplitude is usually:

6. Damping tends to reduce the amplitude of oscillations.

7. Which is an example of damping?

8. At resonance, the amplitude is large mainly because:

9. Even at resonance, amplitude does not grow forever in real systems.

10. The loud sound from blowing across a bottle is an example of:

11. The maximum response of a driven oscillator typically occurs near the ______ frequency.

12. Increasing damping usually makes the resonance peak less sharp (broader and lower).

13. Which change is most likely to change a pendulum’s natural frequency?

14. Resonance is useful in musical instruments because it:

15. If you drive an oscillator at its natural frequency, the phase relationship between drive and motion tends to make energy transfer efficient.

16. A playground swing is easiest to push higher when you push:

17. Resonance can be dangerous in structures if vibrations build to large amplitudes.

18. The frequency range over which resonance is strong is related to the system’s ______ (energy losses).

19. Which is most likely to have a sharp resonance peak?

20. Resonance is not a special force; it is a response effect caused by matching frequencies and efficient energy transfer.