I believe that formula is incomplete, if it is derived from the kinematic equations.
The full formula being [tex]s=ut+\frac{1}{2}at^{2}[/tex]
where:
s is the displacement (or how far she travelled in your question)
u is the initial velocity, which I think can be assumed to be 0 m/s
t is the time taken which is 120 s
a is the acceleration due to gravity which points down in a negative y direction, which is -9.8 m/[tex]s^{2}[/tex]
Since initial velocity, u, is assumed to be 0 m/s the equation becomes:
[tex]s=\frac{1}{2}at^{2}[/tex]
Substitute in a = -9.8m/[tex]s^{2}[/tex] and t = 120 s and calculate your answer.
Tell me what you calculate the answer to be (don't forget units) and I'll let you know if it's right.
