This how it works covers How It Works: KE and Conservation of Energy within Kinetic Energy for GCSE Physics. Revise Kinetic Energy in Energy for GCSE Physics with 15 exam-style questions and 30 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 15 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 15
Practice
15 questions
Recall
30 flashcards
⚙️ How It Works: KE and Conservation of Energy
When an object speeds up, something must be doing work on it — a force acting through a distance. The work done equals the gain in kinetic energy. This is the work-energy theorem.
When an object slows down, its kinetic energy must go somewhere. If it hits a wall, KE transfers to elastic PE (deformation) and then to thermal energy. If brakes are applied, KE transfers to thermal energy of the brake pads via friction. If it compresses a spring, KE transfers to elastic PE. Energy is always accounted for.
In a frictionless system, KE and GPE continuously exchange. A pendulum swings: maximum KE at the bottom, zero KE at the top — and maximum GPE at the top, zero GPE at the bottom. The sum (KE + GPE) remains constant throughout the swing. This is why physicists love the concept of conservation of energy as a problem-solving tool.