aku -- kumar
Last Activity: 14 Years ago
in this kind of problems consider oscillation of centre of mass only that will make ur problem easier to solve
let the pendulum be at some Φ angle with vertical axis, draw f.b.d ur self,
balance the driving force with mg,i.e; F=mg sinΦ
so a= F/m=g sinΦ if Φis very small then sinΦ ≈ Φ,
a = gΦ =g(x/l) » a proportional to x
then use time period formulae, t=2∏ √x/a .