Two pendulums of lengths 1.69 m and 1.44 m start swinging together. After how many vibrations will they again start swinging together?
8 vibrations
10 vibrations
12 vibrations
14 vibrations
T1=2π1.69g,T2=2π1.44gLet shorter pendulum makes (n + I) vibrations then the longer makes n vibrations to come in phase again then n+1T2=nT1 n+1n=T1T2=1.691.44⇒n=12