One end of a string is attached to an object of mass M, and the other end of the string is secured so that the object is at rest as it hangs from the string. When the object is raised to a position X that is a height H above its lowest point and released from rest the object undergoes simple harmonic motion. When the object passes through the equilibrium position Y, it has a speed Which of the following methods could a student use to determine the total mechanical energy E at position Y, and why? A. E = Mug - MgH, because energy changes from kinetic energy to gravitational potential energy as the pendulum swings from position X to position Y
B. E=MgH - M y because energy changes from gravitational potential energy to kinetic energy as the pendulum swings from position X to position Y
C. E = Me, because this equation represents the maximum kinetic energy of the pendulum at position Y if the system has zero gravitational potential energy at position Y
D. E MgHube E = MgH, because this equation represents the maximum gravitational potential energy of the system at position X if the system has zero gravitational potential energy at position Y