A package is dropped from a helicopter moving upwards at 15 m/. If it takes 25.0s before the package hits the ground, how high above the ground was the package when it was released. Disregard air resistance.
I used this kinematic equation
[tex]s_f=s_i +v_i t + 1/2 a (t)^2[/tex]
The Attempt at a Solution
So I set it up with the initial velocity being +15m/s since it is going up and the gravity as -9.80m/s^2 as it is going down.
Here is my question. Is that right? I am completely lost when it comes to g being positive or negative. I understand you use whichever sign coresponds to your setup directions. But in this case I end up with -2688. Do I just disregard the sign on the distance? Or is could it be negative because my set up states the package was released on the x-axis so technically the end position is negative because it's below the axis? So in that case I do change the sign?
I figure this is pretty important to figure out as it can have a major effect on the outcome of these problems.