A 10kg block is suspended from a cable wrapped around a 5kg disk, as shown in the figure. If the spring has a stiffness constant of k=200N/m, determine the natural period of vibration for the system
The power energy of the system is given by
Why is the work produced by the spring positive and the work produced by the weight negative?
Since the spring is opposing the motion and the weight of the block "helps" the motion, I thought the spring did negative work and the weight did positive work.