Mechanical Resonance – Practice


1) A student has three tuning forks that produce different pitches. When each produces a sound and is held close to a wine glass. One of the tuning fork causes the wine glass to vibrate and the other two do not. Explain this observation:

2) The diagram below shows 4 separate masses hanging from a string. Mass A is pushed so that it swings freely back and forth. What would you observe happening to mass B, C and D? Explain your answer:



Quick Answers:

1)The three tuning forks are different and would emit different frequencies after being struck. The tuning fork that causes the wine glass to vibrate would vibrate at a frequency that is equal to the resonant frequency of the wine glass

2) Masses B and C will begin to move. The degree to which they oscillate will vary at any instant

Mass D will begin to oscillate and as it is the same length as A and (assuming it is equal in mass) will have the same resonant frequency as mass A.

This can result in the frequency and amplitude of D eventually becoming equal to mass A

Worked Answers: