600. I forgot the measurement. but 600 is correct
This question involves the concepts of the law of conservation of energy and kinetic energy.
The girl's fastest speed is "3.7 m/s".
According to the law of conservation of energy, the girl will have the fastest speed at mean position, which will be calculated as follows:
Loss in Potential Energy = Gain in Kinetic Energy

where,
v = maximum speed = ?
g = acceleration due to gravity = 9.81 m/s²
Δh = change in height = 1.3 m - 0.6 m = 0.7 m
Therefore,

<u>v = 3.7 m/s</u>
<u></u>
Learn more about the Law of Conservation of Energy here:
brainly.com/question/381281?referrer=searchResults
Answer:
(1) The orbits are ellipses, with focal points ƒ1 and ƒ2 for the first planet and ƒ1 and ƒ3 for the second planet. The Sun is placed in focal point ƒ1.
(2) The two shaded sectors A1 and A2 have the same surface area and the time for planet 1 to cover segment A1 is equal to the time to cover segment A2.
(3) The total orbit times for planet 1 and planet 2 have a ratio a13/2 : a23/2