Problems sets to review and apply equations from Chapter 11
52.Clue: Adjacent nodes are separated by a half-wavelength, as examination of Fig. 11–41b will show.
67. Use the frequency of a simple pendulum given by Eq. 11–11b, f 
1
2
g
.
69.Clue: The spring constant does not change, but the mass does, so the frequency will change. Use Eq. 11–6b to
relate the spring constant, the mass, and the frequency for oxygen (O) and sulfur (S).
84. Clue: The wave speed is given by Eq. 11–12,    f , while the maximum speed of particles on the cord is
given by Eq. 11–7, max  2 Af .
85. Clue: From the given data, A  0.50 m and   2.5 m/4.0 s  0.625 m/s. We use Eq. 11–17b for the
average power, with the density of seawater from Table 10–1.