4. (a) The potential energy stored in a spring is kx'/2, where k is the spring constant and x is the compression in the spring. The force required to compress the spring is kx. The following table gives the data for the 5 springs Force (N) (15) Spring constant k (N/m) 800 500 550 400 300 Use MATLAB to find (i) compression x and potential energy stored in each spring