Warm-Up Exercise for lecture 28

Due 8:00 am, Thurs, 10 Dec 09

Physics 105, Fall 2009

If a vibration is made to happen at a natural oscillating frequency of an object, this is called:
☐ beats
☐ harmonics
☑ resonance
☐ standing waves
☐ traveling waves

Pianos typically have two or three strings for each note. That is, when you press a single key, a small hammer simultaneous strikes two or three strings. T/F: if the strings are slightly out of tune with respect to each other, unwanted beats can form in the pitch when you play the note.
☑ true
☐ false

A flute and a clarinet both play the same note. Two microphones record the sound wave oscillations. T/F: If the oscillations picked up by the microphones are graphed, the two graphs will look the same.
☐ true
☑ false

Ralph is confused by the difference between standing waves and beats, because they are both caused by interference of waves. Help Ralph understand when interference will produce one rather than the other.
Standing waves are caused by two waves of the same frequency that are traveling in opposite directions. Beats are caused by two waves with slightly different frequencies, traveling in the same direction.