1 \begin{problem*}{13.16}
2 A light string with a mass per unit length of $8.00\U{g/m}$ has its
3 ends tied to two walls seperated by a distance equal to three-fourths
4 the length of the string (Figure P13.16). An object of mass
5 $m$ is suspended from the center of the string, putting a tension in
6 the string. \Part{a} Find an expression for the transverse wave speed
7 in the string as a function of the mass of the hanging
8 object. \Part{b} What should be the mass of the object suspended from
9 the string so as to produce a wave speed of $60.0\U{m/s}$.
15 real L=3u; // length of string
16 real D=3L/4; // wall separation
17 real dx = 12pt; // length of bonus string for hanging mass & wall above string
18 real r = 12pt; // radius of hanging mass
20 Mass m = Mass(radius=r, L="m");
21 pair junction = m.center + (0, r+dx);
22 real theta = asin(D/L) * 180 / pi;
23 pair wall_join_r = junction + L/2*dir(90-theta);
24 pair surf_ur = wall_join_r + (0, dx);
25 pair surf_lr = (surf_ur.x, m.center.y - r - dx);
26 Surface s_r = Surface(pFrom=surf_lr, pTo=surf_ur);
27 pair wall_join_l = xscale(-1)*wall_join_r;
28 pair surf_ul = xscale(-1)*surf_ur;
29 pair surf_ll = xscale(-1)*surf_lr;
30 Surface s_l = Surface(pFrom=surf_ul, pTo=surf_ll);
31 Distance d = Distance(pFrom=wall_join_l, pTo=wall_join_r, L="$3L/4$");
33 draw(m.center -- junction);
34 draw(wall_join_l -- junction -- wall_join_r);