**Your
answer to Q110: **Sorry,
your answer is **not** correct. The term "dynamic parameters" refers
to things like tension of a string, for example, or the force of gravity on
water, when there are waves on those media. An "inertial parameter" is the density
or mass of the medium.

Help: *Fundamentals of
Sound, *Secs. 1-G, 1-H.

Or, would you like a HINT?

You should really try to
work out the answer on your own, but if you insist on reading it, the correct
answer is HERE.

Return to Question 110.

**Hint
for Q110: **How would you change the wave velocity of a wave on a string?
How would you go about changing the frequency of a sinusoidal wave?

Return to Question
110.

**Your
answer to Q110: **Congratulations, your answer is **correct!**

If you like, you can compare your answer to the "official" correct answer.

Return to Question 110.

**Correct
answer to Q110: **The wave velocity depends on the properties
of the medium such as the tension of a string or its density (the dynamical
and inertial properties mentioned). However a wave of any frequency can be placed
on the string just by jiggling your hand up and down more or less often. When
you change the frequency you change the wavelength such that the formula in
a) holds; the higher the frequency the smaller the wave length — with
the wave velocity staying constant unless you change the medium. Thus g) is
correct.

Return to Question
110.

**Your
answer to Q115: **Sorry, your answer is **not **correct. What are
the differences between standing waves and traveling waves?

Help: *Fundamentals of
Sound, *Sec. 2-C.

Or, would you like a HINT?

You should really try to work out the answer on your own, but if you insist on reading it, the correct answer is here.

Return to Question
115.

**Hint
for Q115:** One makes a standing wave by enforcing boundaries on the
medium so that there is reflection at the boundaries. For a string tied at both
ends, the ends are fixed. What condition does that put on the wavelength?

Return to Question 115.

**Your
answer to Q115: **Congratulations, your answer is **correct**!

If you like, you can compare
your answer to the "official" correct answer.

Return to Question 115.

**Correct
answer to Q115: ** When you tie the ends of a string down the wavelength
must be such that there are zeros (nodes) of the wave at the ends. This means
that we cannot have just any wavelength; the wavelength must be adjusted to
fit into the space properly. Thus only certain wavelengths, and hence frequencies,
are allowed and b) becomes true. As in Question 110 c) and d) are also true.
Thus the correct answer is f).

Return to Question
115.

**Your
answer to Q120: **If you got 6ft you are correct; if not, you
have made an error. You measure wavelength of a standing wave just like any
other wave. Note that the wave velocity information given is irrelevant. Try
again.

Help: *Fundamentals of
Sound, *Sec. 2-C.

You should really try to work out the answer on your own, but if you insist on reading it, the correct answer is HERE.

Return to Question
120.

**Correct
answer to Q120: **The wavelength is the peak-to-peak distance, but can
also be measured in the following way: start at the left end, a node, move past
the first crest to the next node (1/3 of the way along), move past the trough
to the third node (2/3 of the length). You have moved a wavelength and it is
2/3 of the entire string length of 2/3 of 9 = 6ft

Return to Question
120.

**Your
answer to Q125: **Sorry, your answer is **not **correct. Recall
that the fundamental = first harmonic; first overtone = 2nd harmonic; second
overtone = 3rd harmonic, etc.

Help: *Fundamentals of Sound, *Sec. 2-C.

Or, would you like a HINT?

You should really try to work out the answer on your own, but if you insist on reading it, the correct answer is here.

Return to Question 125.

**Hint
for Q125: **You can determine the harmonic or overtone by counting the
number of antinodes. The fundamental has one antinode.

Return to Question 125.

**Your
answer to Q125: **Congratulations, your answer is **correct**!

If you like, you can compare your answer to the "official" correct answer.

Return to Question
125.

**Correct
answer to Q125: **This is the 3rd harmonic or the 2nd overtone. The
fundamental (or 1st harmonic) has just one antinode fitting between the two
walls (and two nodes—at the ends). The first overtone (2nd harmonic) has
two antinodes (or three nodes); and the second overtone (3rd harmonic) has three
antinodes (four nodes). This problem's figure shows three antinodes and so g)
is the correct answer.

Return
to Question 125.

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