Encountered non-numerical value for a derivative at t==0.

Questions
1

enter code here
m1 := 0.04 (Hi all, this message keeps on popping up even though I think I have defined every single variable numerically. Are there other possible reasons? Thank you)
m2 := 14
g := -9.81
l1 := 1/4.75
l2 := 3.75/4.75
lb := 1/2 - l1
lambda := 1/10
mb := lambdaSqrt (m1)(l1 + l2)
Ib := 1
ls := 1
dmax := ((2 + Sqrt[2])/m2)(m1l1 - mblb)
e := dbest/dmax
dphi := phib[t] - phis[t]
alphab := (m2l2ls)/(m1l1^2 + m2l2^2 + mblb^2 + Ib)
omegabsquared :=
g*(m1l1 - m2l2 - mblb)/(m1l1^2 + m2l2^2 + mblb^2 + Ib)
alphas := l2/ls
omegassquared := g/ls
s := NDSolve[{phis’‘[t] ==
alphas*((phib’[t])^2Sin[-dphi] + phib’‘[t]Cos[-dphi]) -
omegassquaredSin[phis[t]],
phib’'[t] ==
alphab((phis’[t])^2Sin[dphi] + phis’'[t]Cos[dphi]) -
omegabsquaredSin[phib[t]], phis[0] == Pi/2, phib[0] == 3Pi/4,
phis’[0] == 0, phib’[0] == 0}, {phib[t], phis[t]}, {t, 0, 100}]
s

2

Resolved