T1=2派*根号下(l1/g)
l1=(T1)^2*g/4派^2
T2=2派*根号下(l2/g)
l2=(T2)^2*g/4派^2
因为l1-l2=a
所以a=(T1)^2*g/4派^2-(T2)^2*g/4派^2
g=4a派^2/[(T1)^2-(T2)^2]
T1=2派*根号下(l1/g)
l1=(T1)^2*g/4派^2
T2=2派*根号下(l2/g)
l2=(T2)^2*g/4派^2
因为l1-l2=a
所以a=(T1)^2*g/4派^2-(T2)^2*g/4派^2
g=4a派^2/[(T1)^2-(T2)^2]