Answer:
Explanation:
Given
height of girl at top point is [tex]h_1=3.9\ m[/tex]
height at bottom point is [tex]h_2=0.9\ m[/tex]
Suppose girl possess maximum velocity at bottom point so her kinetic energy is converted to Potential energy
kinetic energy [tex]K=\frac{1}{2}mv^2[/tex]
Gain in Potential Energy [tex]\Delta U=mg(h_1-h_2)[/tex]
[tex]K=\Delta U[/tex]
[tex]\frac{1}{2}mv^2=mg(h_1-h_2)[/tex]
[tex]v=\sqrt{2g(h_1-h_2)}[/tex]
[tex]v=\sqrt{2\times 9.8\times (3.9-0.9)}[/tex]
[tex]v=\sqrt{58.8}[/tex]
[tex]v=7.66\ m/s[/tex]
