346 CHAP. 16 MECHANICAL WAVES n - 2 n+ 1 n + 2 1 wwwww wwww wwwwro y1 = 2 + (2x - 30)2 m -1 Y2 =2 + (2x + 31 - 6)2 m. FIGURE 16.34 Problem 14. where x is in meters and / is in seconds. (a) At what position will the resultant displacement always be zero? (b) At what 15. (1) (a) Show that the wave speed for transverse waves on a time will the resultant displacement be zero everywhere? Slinky of mass m and spring constant k is LVk/m, where [Hint: Choose convenient values for x or t.] L, the stretched length, is much larger than the unstretched 17. (I) A wave travels in the negative direction at 25 m/s along a length. (b) Show that the time required for a pulse to travel string. The period is 20 ms. At x = 0 and t = 0, the particle the length of the Slinky is independent of the length. velocity is -2 m/s and the vertical displacement is 3 mm. 16.) (I) Two wavefunctions in a medium are given by Write the wavefunction y(x, ()