Students should draw a curve through their data points. The part of this graph where x is positive corresponds to the above plot of data points. Dr the spring is from the fulcrum. The below picture was made using The Geometer's Sketchpad . It shows a number balance with a weight on the left side and a spring balance on the right.
Students can exert forces from different pegs on the right side of the balance.
And after experimenting with a stationary weight, students can experiment further by changing the location of the weight. In the above picture, Dl represents the distance the weight is from the fulcrum. Similarly, Dr represents the distance the spring balance is from the fulcrum. By experimenting with the locations of both the weight and the spring balance, students can discover Varignon's theorem , one of the most useful principles of mechanics. This theorem states that the moment of a force about any point is equal to the sum of the moments of the components of the force about the same point.