Wave Motion 2 Question 46

46. The vibrations of a string of length 60cm fixed at both ends are represented by the equation

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Answer:

Correct Answer: 46. (a) 23cm (b) x=0,15cm,30cm etc

(c) Zero

(d) y1=2sin(πx1596πt) and y2=2sin(πx15+96πt)

Solution:

  1. (a) y=4sinπx15cos(96πt)=Axcos(96πt)

Here, Ax=4sinπx15

at x=5cm,Ax=4sin5π15=4sinπ3=23cm

This is the amplitude or maximum displacement at

x=5cm

(b) Nodes are located where Ax=0

 or πx15=0,π,2π or x=0,15cm,30cmetc.

(c) Velocity of particle,

vp=|yt|x= constant =384πsin(πx15)sin(96πt)

At x=7.5cm and t=0.25s

vp=384πsin(π2)sin(24π)=0

(d) Amplitude of components waves is A=42=2cm

ω=96π and k=π15

Component waves are,

and

y1=2sin(π15x96πt)y2=2sin(π15x+96πt)



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