In order to begin moving a Mass(Accelaration) will solve for the force required to move the skateboard
Mass(9.8) will give you the force needed to move the skateboard originally
Answer: This will be based on how much strength she put into the rock when throwing it
Explanation:
Speed can be found through the application of concepts related to potential energy and kinetic energy, for which you have


Where,
m = mass
v = Velocity
g = Gravitational acceleration
h = Height
Re-arrange to find the velocity we have,




Therefore the speed at which water squirts out of the hole is .3253m/s
We know, work done = Weight * Displacement
w = 3.76 * 2
w = 7.52 J
In short, Your Answer would be: 7.52 Joules
Hope this helps!