3 đoạn bằng nhau
\(\Rightarrow\left\{{}\begin{matrix}t_1=\sqrt{\dfrac{2S_1}{a}}\\t_2=\sqrt{\dfrac{2.2.S_2}{a}}\\t_3=\sqrt{\dfrac{2.3S_3}{a}}\end{matrix}\right.\)
t2=1s\(\Rightarrow\dfrac{S}{a}=\dfrac{1}{4}\)
\(T\approx2,931\left(s\right)\)
thay vào T=t1+t2+t3=