1. The problem statement, all variables and given/known data It's been a little while since I did one of these. My question is: We have to use http://phet.colorado.edu/sims/mass-spring-lab/mass-spring-lab_en.html to find the measurement of k, the spring factor using two different methods. For the method I am looking at, is the static method. 2. Relevant equations F(x)=-kx F(x)=-k(x-x_0) plot L(mass)=(x-x_0) = -F/k = -mg/k 3. The attempt at a solution What I am doing is using the various weights and measuring the displacement with the giving centimeter ruler. As far as error measurement I understand the each calculation of displacement will by +/- 0.5 cm as the error measurement. My work: So, if I have a table of values (.05kg, .05m), (.1kg, .1m), (.25kg, .24m) I can use these values to calculate k, the spring constant. From the equation: K=-m*g/(x-x_0) From point one, we see K= - (0.05kg*9.8m/s^2 )/ (0.05m) = -9.8N/m From point two we see K = - (.1kg*9.8m/s^2)/(.1m) = -9.8 N/m From point three we see K = - (.25kg*9.8m/s^2) / (.24m) = -10.21 N/m conclusion Here I have found the value of K. Did I find it correctly? Now for error the question states: "For example, how accurately can you measure the displacement of the spring and what is the effect of the error of that measurement on your determination of the spring constant?" Do I just write +/- 0.5 once I average out the k values?