Q.4) (4 Marks) An object is oscillating at the end of a spring of force constant 250 N m. The following figure shows a graph of its position x as a function of time t. x (cm) (a) At what times is the mass not moving (v0)? (b) How much energy did this system originally contain (at t-0)? r() (e) How much energy did the system kose between t-1 s and t4 s? Where did this energy go?