| English | Elastic potential energy |
|---|---|
| Bahasa Melayu | Tenaga keupayaan kenyal |
| 中文 | 弹性势能 |
Definition
The energy stored in a spring or elastic object when it is stretched or compressed.
In exam terms
Elastic potential energy is the energy stored in a spring or elastic object when it is stretched or compressed. It equals the work done by the applied force, and while Hooke's law holds it is given by E = ½ F x = ½ k x², measured in joules (J).
On a force–extension graph it is the area under the straight line.
For example, a spring with spring constant 200 N m⁻¹ stretched by 0.10 m stores E = ½ × 200 N m⁻¹ × (0.10 m)² = 1.0 J. When released, this stored energy can change into kinetic energy of the object.
Don't confuse it with kinetic energy
Do not confuse elastic potential energy with kinetic energy. Elastic potential energy is stored because of deformation and depends on extension; kinetic energy depends on motion and speed.
It also differs from gravitational potential energy, which depends on height. All three share the unit joule (J).
In Paper 2 this is usually asked with 'Calculate…' using ½ k x² or the area under a force–extension graph, or with 'Explain the energy change' as a spring is released. Show the squaring of the extension and keep joules (J) in the answer.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)