- Now that you have your value for your spring constant for spring 3, use it to tind the magnitude of the masses of the unknown weights. Use the data table below for your measurements and avoid any fat jokes about the red mass, he's a little sensitive. Also, find the potential energy stored in each spring while each of the weights are being hung. Show ofthe calculations you used to solve for the mass of one of the unknowns in the space provided below the table. nknown Mass Green Gold Red Je for k for spring 3 =