Effective Spring Constant: In Part I you measured the keffective of the two springs acting together. If the two springs had ki and k2 individually, how would they combine to get keff? Procedure Part I: Measuring the Spring Constant In this part, we will measure the the displacement for various amounts of force, and use the slope to determine the spring constant. First, disconnect the springs so the cart can move freely, and (as always) level your air track. While you have everything disconnected, record (at the top of Part II) the mass of your glider and the mass of the two springs (combined). Then, reconnect the two springs, each from one end of the cart to the corresponding end of the track. Then, loop a string (tied to the cart) through the pulley on the other end (ensuring it doesn't Hang a 20g mass from the spring, and record the position with this mass.