Question

A wire of uniform cross-section is stretched between two points 100cm apart. The wire is fixed at one end and a weight is hung over a pulley at the other end. A weight of 9kg produces a fundamental frequency of 750Hz. (a) What is the velocity of the wave in wire? (b) If the weight is reduced to 4kg, what is the velocity of wave?

Answer 1

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Answer 2

Given :

Weight = 9kg

Frequency = 750Hz

Distance between points = 100cm

To find :

a) velocity of the wave in wire

b) velocity of wave when weight is reduced to 4kg

Solution :

• a)    V₁= 2Lf

           =2×100×750  

           =150000 cm/s = 1500cm/s

          velocity of the wave   is 1500cm/s

• b)      V₁/V₂ = √T₁/T₂

         1500/V₂ = √4/9

         1500/V₂ = 2/3

         V₂ =1000m/s

         velocity of wave when weight is reduced to 4kg Is 1000m/s