[填空题]
One end of a horizontal string is atta( :hh4o g* vbohcx9+)dqh9my oched to a small-amnz+ gh5t/uoen-p0 2k84 wsdbaplitude mechanical 60-Hz vibrator. The string’s mass per unit length 0ewa5 -d /h2on gst+p 8zuk4bnis $3.9 \times10^{ -4}$ kg/m The string passes over a pulley, a distance L = 1.50 m away, and weights are hung from this end, Fig. 11–53. What mass m must be hung from this end of the string to produce
(a) one loop,(round to one decimal place) $\approx$ kg
(b) two loops, kg
(c) five loops of a standing wave? Assume the string at the vibrator is a node, which is nearly true. kg
