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Waves

Question
CBSEENPH11026396

Four massless springs whose force constants are 2k, 2k, k and 2k respectively are attached to a mass M kept on a frictionless plane as shown in the figure. If the mass M is displaced in the horizontal direction, then the frequency of the system is

  • 12π k4M

  • 12π4kM

  • 12πk7M

  • 12π 7kM

Solution

B.

12π4kM

     

Two springs on the L.H.S. of mass M are in series and two springs on the R.H.S. of mass M are in parallel. These combinations of springs will be considered in parallel to mass M. Thus effective spring constant,

     K = 2k × 2k2k + 2k + ( k + 2k)

        = 4k

∴ Frequency ν = 12π KM

                   ν  = 12π 4kM