Phys102
Term: 131
Online HW-Ch16-Lec02
Q1:
Sinusoidal water waves are generated in a large ripple tank. The waves travel
at 20 cm/s and their adjacent crests are 5/.0 cm apart. The time required for
each new whole cycle to be generated is:
A. 100 s
B. 4.0 s
C. 2.0 s
D. 0.5 s
E. 0.25 s
Ans:
E
Q2:
A sinusoidal wave of frequency 500 Hz has a speed of 350 m/s. How far apart two
points that differ in phase by π /3 rad. (Give the answer in three significant figures
and SI units)
Ans:
Using v = fλ, we find the length of one cycle of the wave is:
λ=
350
= 0.700 m = 700 mm.
500
A cycle is equivalent to 2 λ radians, so that λ /3 rad corresponds to one-sixth of a
cycle. The corresponding length, therefore, is λ /6 = 700/6 = 117 mm
Q3:
The tension in a string with a linear mass density of 0.010 kg/m is 0.40 N. A
sinusoidal wave with a wavelength of 20 cm on this string has a frequency of: (Give
the answer in three significant figures and SI units)
Ans:
τ
0.4
v=� =�
= 6.32 m/s
µ
0.01
λ = 20 cm = 0.2 m
v = λf ⇒ f =
v
= 31.6 Hz
λ
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