College Physics
posted by Jen on .
An object is suspended from a spring and vibrates with simple harmonic motion. At an instant when the displacement of the object is equal to onehalf the amplitude, what fraction of the total energy of the system is kinetic and what fraction is potential?

Potential energy of a vibrating spring is proportional to the square of the displacement (P.E = kx^2/2, where k is the spriong constant). At maximum displacement, ALL of the energy is potential energy, because motion temporaily stops and KE is zero. At 1/2 maximum displacement, the P.E. is 1/4 of that total energy. That means that 3/4 must be kinetic energyn there.