Question

at what point in this sequence of events is potential energy being converted to kinetic energy?
a when the spring is recoiling
b when the spring is fully recoiled
c when the spring is fully stretched
d when the spring is stretching

Explanation:

To determine when potential energy (PE) converts to kinetic energy (KE), recall: PE is stored (e.g., in a stretched/compressed spring), KE is motion.

• Option a: When the spring recoils, the stored PE (from being stretched) is used to move the spring, so PE → KE.
• Option b: Fully recoiled means motion stops, KE is low, PE is minimal (no stretch/compression), so no conversion here.
• Option c: Fully stretched: PE is maximum (stored), KE is zero (no motion), so KE → PE (opposite conversion).
• Option d: Stretching: Work is done to store PE, so KE (or work) → PE (opposite conversion).

Answer:

a. when the spring is recoiling