Why Does a Negative Spring Constant Give a Nonreal Period in Oscillation?

[bmx_Freestyle]

Ok so i am doing a lab...and i graphed my data points and my slope turned out to be negative.
The y-axis is in Newtons and the x-axis is in Meters.
So my teacher said the the slope=k (constant)
period of an oscillation formula: T=2pi(m/k)^1/2
But my k is negative so when i substitute all my numbers, i get a "Nonreal answer"
What did i do wrong?

 

[PeterO]

Ok so i am doing a lab...and i graphed my data points and my slope turned out to be negative.
The y-axis is in Newtons and the x-axis is in Meters.
So my teacher said the the slope=k (constant)
period of an oscillation formula: T=2pi(m/k)^1/2
But my k is negative so when i substitute all my numbers, i get a "Nonreal answer"
What did i do wrong?

You said this was a prac, and you were plotting the results.

What instrument were you using to measure the [Force, in] Newtons;

What instrument were you using to measure the metres;

that you eventually plotted?

What experiment were you actually doing? A pendulum? A mass on a spring? A mass in an inertial balance?