10. Conservation of Energy

In which of the following scenarios is $\mathrm{elastic} \mathrm{potential} \mathrm{energy}$ present?

Which of the following scenarios generates the most elastic potential energy in a spring with spring constant $k$ and equilibrium length, assuming the same spring is used in each case?

For a spring obeying Hooke's law, doubling which of the following quantities would cause the largest increase in the spring's elastic potential energy $U$?

When a spring is stretched by an external force and held at a fixed length, does the spring possess elastic potential energy?

A 4-kg block moving on a flat surface strikes a massless, horizontal spring of force constant 600 N/m with a 20 m/s. The block-surface coefficient of friction is 0.5. Calculate the maximum compression that the spring will experience.