Sponsor Area

Mechanical Properties Of Fluids

Question
CBSEENPH11020232

A wire stretched between two rigid supports vibrates in its fundamental mode with a frequency of 45 Hz. The mass of the wire is 3.5 × 10–2 kg and its linear mass density is 4.0 × 10–2 kg m–1. What is (a) the speed of a transverse wave on the string, and (b) the tension in the string?

Solution
(a) Mass of the wire, m = 3.5 × 10–2 kg 
Linear mass density, μ =straight m over straight l = 4.0 × 10-2 kg m-1 

Frequency of vibration, v = 45 Hz
∴ length of the wire, l =straight m over straight mu 
                                 = fraction numerator 3.5 space cross times space 10 to the power of negative 2 end exponent over denominator 4.0 space cross times space 10 to the power of negative 2 end exponent end fraction space equals space 0.875
The wavelength of the stationary wave (λ) is related to the length of the wire by the relation, 
                              straight lambda space equals space fraction numerator 2 space straight l over denominator straight m end fraction

where, 
n = Number of nodes in the wire. 
For fundamental node, n = 1:
λ = 2

λ = 2 × 0.875
   = 1.75 m 
The speed of the transverse wave in the string is given as, 
= νλ
   = 45 × 1.75
   = 78.75 m/s
(b) The tension produced in the string is given by the relation, 
v2µ 

   = (78.75)2 × 4.0 × 10–2
   = 248.06 N