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Sci Advisor
PF Gold
P: 1,776
 Quote by Lucy Yeats I've got the first bit: L=(m/2)(l^2)(dθ/dt)^2-mgl(1-cosθ) E.O.M.: d2θ/dt2+(g/l)sinθ=0 d2θ/dt2+(g/l)θ=0 in the small angle approximation, which is S.H.M. with ω^2=√(g/l) (though I'm not sure about this as there's no minus sign in the E.O.M.) so T=√(l/g)
Careful here, $\omega$ is that angular velocity in radians per time unit. Your T is the time to travel one radian (of the oscillatory cycle) not time per cycle. You need to multiply by $2 \pi$.