Given:
The speed of Sydney is,
[tex]v=5\text{ m/s}[/tex]let the maximum height she reaches is h.
From the conservation of energy, we can write,
[tex]\begin{gathered} \frac{1}{2}mv^2=mgh \\ h=\frac{v^2}{2g} \end{gathered}[/tex]Substituting the values we get,
[tex]\begin{gathered} h=\frac{5\times5}{9.8} \\ =2.55\text{ m} \end{gathered}[/tex]Hence, the maximum height is 2.55 m.