Solution:
Solution
The frequency of vibration of a string
n=p2l√Tm
Also number of loops = Number of antinodes.
Hence with 5 antinodes and hanging mass of 9 kg. we have p=5 and T=9g
So,
n1=52l√9gm
With 3 antinodes and hanging mass M we have p=3 and T=Mg so,
n2=32l√Mgm
∵n1=n2
52l√9gm=32l√Mgm
Squaring both side we get
25×9=9×M
M=25 kg