10 minutes maximum! Can you do it in 5?

 1. Which of the following sentences best describes the effect of resonance on the amplitude of vibration of a system?

  • A. The amplitude increases when the natural frequency matches the resonant frequency of the system
  • B. The amplitude increases when the driving frequency matches the natural frequency of the system
  • C. The wavelength increases when the natural frequency matches the resonant frequency of the system
  • D. The wavelength increases when the driving frequency matches the natural frequency of the system

2&3: A measuring cylinder containing some water is used to make an air column closed at one end.

The tuning fork is hit so that it vibrates. The water level in the cylinder is adjusted until the system resonates and a louder sound is heard.

resonance of air column in measuring cylinder

2. What part of the system shown is connected with the driving frequency and the natural frequency of vibration?

  driving frequency natural frequency
A tuning fork water column
B air column tuning fork
C water column tuning fork
D tuning fork air column

3. The resonant frequency in this experiment is fr. Which of the graphs below best shows how the amplitude changes in this experiment?

resonance graphs x4

4. When soldiers march across bridges, they 'break step' so that their feet do not hit the floor at the same time. Which of the following sentences best describes the reason for doing this?

  • A. So that the bridge is not damaged by excessive forces
  • B. So that the bridge does not move downwards
  • C. To prevent the driving frequency of marching making the bridge resonate, causing damage
  • D. To prevent the natural frequency of marching making the bridge resonate, causing damage

5-8: These questions are about damping and resonance.

 tacoma narrows bridge GIF
Tacoma Narrows Bridge from Gifer

5. What is the effect of damping on the amplitude and resonant frequency of a resonating system?

  amplitude resonant frequency
A decreases small decrease
B increases small decrease
C decreases small increase
D increases small increase

6-8: The following graphs show the displacement of an oscillating system over time:

resonance with daming graphs x4

Which graph best represents....

  
6. light damping?
7. heavy damping?
8. critical damping?

9&10: A child's swing has a natural frequency of 0.5 Hz and therefore a time period of 2 seconds. An adult pushes the swing at regular intervals.

 

childrens swing

Image by Ulrike Mai from Pixabay

9. To make the swing have a higher amplitude so that it goes higher in the air, the swing can be pushed every....

  • A. 1 second or 2 seconds
  • B. 1 second or 4 seconds
  • C. 2 seconds or 4 seconds
  • D. 2 seconds or 3 seconds

10. If the swing is not pushed, it slows down and stops due to air resistance. Which of these sentences best describes the effect of air resistance on the swing?

  • A. Light damping produced by a force that is dependent on the displacement from the origin
  • B. Light damping produced by a force that is dependent on the velocity
  • C. Heavy damping produced by a force that is dependent on the velocity
  • D. Heavy damping produced by a force that is dependent on the displacement from the origin