Mass 'm' is suspended from the mass-less pulley which itself is supported by two springs connected to each other as shown. If the mass is slightly displaced from its equilibrium position, find the frequency of resulting SHM of mass 'm'.
Let mass m be
displaced by a distance of x from its equilibrium position
so
that the additional elongation in spring 1 & 2 are x1 &
x2 respectively, then
2x=x1+x2 -----(1)
Also
since tension in both springs are same.
T=k1x1=k2x2
from
(1) we have
2x=x1(1+k1k2)
∴T=k1x1=2k1x1+k1k2=2k1k2xk1+k2
T′=2T=4k1k2xk1+k2
T
and T′ are additional tension, over and above the tension already
present at equilibrium. hence, for the mass
m
−md2xdt2=4k1k2xk1+k2
f=12π√4k1k2(k1+k2)m