Physics · Grades 10–12
Elastic energy in a spring
Convert extension to metres, then square it; the spring is ideal and linear.
Rule and assumptions
Convert extension to metres, then square it; the spring is ideal and linear.
E = ½kx²
Worked examples
An ideal linear spring has k = 410 N/m and extension 24 cm. Find the stored elastic energy. Round to 3 decimal places if needed. Answer in J.
E = ½kx² 0.5 × 410 × (24/100)² = 11.808
11.808 J
An ideal linear spring has k = 500 N/m and extension 33 cm. Find the stored elastic energy. Round to 3 decimal places if needed. Answer in J.
E = ½kx² 0.5 × 500 × (33/100)² = 27.225
27.225 J
Try two questions
An ideal linear spring has k = 540 N/m and extension 44 cm. Find the stored elastic energy. Round to 3 decimal places if needed. Answer in J.
An ideal linear spring has k = 720 N/m and extension 36 cm. Find the stored elastic energy. Round to 3 decimal places if needed. Answer in J.
Answers and reasoning
Answers and marking notes
- 52.272 J
E = ½kx² 0.5 × 540 × (44/100)² = 52.272
- 46.656 J
E = ½kx² 0.5 × 720 × (36/100)² = 46.656
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · independent educational and translation review required. Suggested grades are not official curriculum alignment.