# Mass on a vertical spring problem

Hi guys, I need some help with my physics lab I've got to do tomorrow. The thing is that I have been assigned to do this lab today so I only had 1 day to take these measurements and to prepare what i have. I'm in AP Physics B.

Here goes.

Basically my teacher wants us to find what the minimum height is going to be when a mass, attached to a spring, is released. So basically, how low will the object (in my case it's a pikachu! :P ) go once it's released. I have to be within 10cm to get an A+ if not I get an F. Just how great is my teacher?

I only had like 10 minutes to measure this but this is what i have (i'm so embarrassed)

when i stretch the spring to .9m, the force gauge attached to it reads 2.5 N. So when i apply F=kx, k= 2.78... rounded.

EDIT: I want to add that i don't know the length of the spring when it's fully compressed (in equilibrium... it's a very thing spring... like a slinky) but i would guess that it's 15cm. I can still measure that tomorrow and apply it to any formula if anyone is kind enough to guide me towards.

I know that 1/2kx^2=mgh but how in god's name do i apply that. I have no Idea where to start. I tried finding x, but i doubt that, that is correct. We have never been taught this (this is how we learn... by "mistakes" and getting F's).

Can i apply the fact that at it's lowest point, pikachu has a velocity of 0? I might be able to do like falling object problem where the spring is pulling back is the -a. Any help?

And yes... i looked in my book and even on the internet...

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