Question

What is the magnitude of the change in potential energy of the block-spring system when it travels from its lowest vertical position to its highest vertical position?

Answer 1

Answer:

 ΔU = 2 mg h

Explanation:

In a spring mass system the potential energy is U = m g h

where h is measured from the equilibrium point of the spring

the potential energy at the highest point is

         U₁ = m g h

the potential energy at the lowest point is

         U₂ = m g (-h)

instead in this energy it is

          ΔU = 2 mg h

In this two points the kinetic energy is zero, but there is elastic potential energy that has the same value in the two points, so its change is zero