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124.

Problem 19.23 (RHK)

A non-uniform wire of length L and mass M has a variable linear mass density given by , where x is the distance from one end of the wire and k is a constant. We have to show (a) that . (b) We have to show that the time t required for a pulse generated at one end of the wire to travel to the other end is given by , where F is the tension in the wire.

Solution:             Click For PDF Version

(a)

Mass density of the wire is . Therefore, mass of the wire is

(b)

Speed of wave motion in the wire will be a function of position x as mass density varies with x. As the wire is under uniform tension F, we have

Therefore, the time t required by a wave pulse generated at one end to travel to the other end of the wire will be