Solving Hooke's Law Troubleshooting Homework

[garr6120]

Homework Statement

i am doing this hooke's law lab to figure out a spring's force constant. I am plotting Force vs. Extension on a graph and then i can calculate the k value using slope however, i keep getting a quadratic instead of a linear line.

Homework Equations

The Attempt at a Solution

I found out the values for my force but multiplying the mass of the weight on the spring by the force of gravity; 9.81 m/s^2. i then had to calculate my extension which i calculated by subtracting the masses extension of the spring by the equilibrium position. Here is a table of values to show you:
mass (kg) Extension (m) Force (N)
0.0 0.000 0.0000
0.1 0.008 0.0008
0.2 0.010 0.0020
0.3 0.015 0.0045
0.4 0.021 0.0084
0.6 0.026 0.0156
0.8 0.032 0.0256
1.0 0.041 0.0410

 

[SteamKing]

There's something about your table which is confusing. If the mass = 1.0 kg, shouldn't the force acting on the spring be 9.8 N approximately? How come your table indicates the force is 0.041 N?

Similarly, if the mass = 0.1 kg, shouldn't the force be 10% of that for a mass of 1.0 kg? How did you get 0.0008 N?

 

[Bystander]

You show three columns of numbers. Which column is what?

 

[garr6120]

ya sorry steamking i don't know why but i put my force into excel so that my mass would multiply by my extension instead of the force of gravity oops. one more question does 215.4 N/m sound right based on this data?

 

[SteamKing]

ya sorry steamking i don't know why but i put my force into excel so that my mass would multiply by my extension instead of the force of gravity oops. one more question does 215.4 N/m sound right based on this data?

Why don't you show your calculation of this value?

 

[garr6120]

On the graph that i created i used the points (0, 0) and (0.039, 8.4000). I put these into the slope equation $\frac{force_2-force_1}{extension_2-extension_1}$, $\frac{8.4000 N-0.0000 N}{0.039 m-0.000 m}$ therefore, $k=214.4 \frac{N}{m}$

 

[SteamKing]

Why did you throw out the last reading when the mass = 1.0 kg?