From: Mr. Abdul Majeed M. M. []
Sent: Wednesday, April 02, 2003 2:12 PM
Subject: Review-chapter-16

KFUPM (Physics)


Review: Chapter 16 Wave Motion


Q 1.  A rope of mass 0.45 Kg is stretched between two supports 30 m apart.  If the tension in the rope is 2400 N, how long does it take a pulse to travel from one support to the other ? (Ans: 0.075 s)


Q 2.   The speed of a transverse wave propagating along a thin cylindrical copper wire is 200 m/s.  Find the speed of such a wave along a second copper wire of half the diameter, assuming the tension is the same in both cases.  (Ans: 400 m/s)


Q 3.   At t = 0, a transverse wave pulse is a wire is described by the function


Y (X,0) = 8 / ( x2 + 111)

Where x and y are in cm.  Calculate y at x = 3 and t = 1 s if the wave is traveling in the negative x direction with a speed of 4 m/s.  (Ans: 0.05 m).


Q 4.  A transverse wave in a string is described by

            Y = 5.0 som (2 * x 3 * t)


Where x and y are in cm and t in s.  what is the magnitude of the transverse acceleration for the point located at x = 2 cm ?


Q 5.  Consider a transverse wave in a long string described by


Y = 0.200 * sin (15 * x 2 * PI * t + 3),

Where x and y are in cm and t is in s.  what is the displacement of a point on the string at x = 2.5 cm and t = 3.51 s ?  (Ans: 0.0785 cm)


Q 6.  A traveling wave train on a string is harmonic, and its transverse displacement is given by y = 3.0 cos (PI * x 4 * PI * t)


Where x and y are in cm and t is in s.  Calculate the power required to generate these waves if the string has a length of 20 m and a mass of 50 g.  Assume all the power produced by the source is delivered to the string.  (Ans: 7.1 * 10(6))


Q 7.  Harmonic wave 15 cm in amplitude are to be transmitted along a string that has a linear density of 4 * 102 Kg/m.  if the maximum power delivered by the source is 500 W and the string is under a tension of 200 N, what is the highest vibrational frequency at which the source can operate ?  (ans: 20 Hz)


Q 8. Two strings with linear densities mu1 and mu2 are joined together and are under the same tension.  If a wave has a wavelength of 2.0 cm in string 1, what is the wavelength in string 2 ?  (Ans: 2 * sqr (mu1/mu2)cm)


Q 9.  Consider the following sinusoidal wave

Y (x,t ) = 10 cos (0.2 x 100 t)

Where x,y are in cm and t is in s.  At a given instant, let point A be at the origin 9x = 0 ) and point B be the first point along x that is 90 degrees out of phase with point A.  What is the coordinate of point B ? (ans: 7.85 cm).