Find the time period of the oscillation of mass m in figures.
(i) 2π√mk1+k2
(ii) 2π√m(k1+k2)k1k2
(iii) 2π√m(k1−k2)k1k2
a) Equivalent spring constant k=k1+k2 (parallel)
T=2π√Mk=2π√mk1+k2
b) Let us, displace the block m towards left through displacement `x'
Resultant force F=F1+F2=(k1+k2)x
Acceleration (F/m)=(k1+k2)xm
Time period T=2π√displacementAcceleration=2π√xx(k1+k2)m=2π√mk1+k2
The equivalent spring constant k=k1+k2
c) In series combination, let equivalent spring constant be k.
So, 1k=1k1+1k2=k2+k1k1k2⇒ k=k1k2k1+k2
T=2π√Mk=2π√m(k1+k2)k1k2