5.2.4—EK = 1/2 mv2
- Syllabus
- 9702–2028–2029
- Objective
- 5.2.4
- Level
- AS
Kinetic energy is the energy of motion, E_K=½mv²
The kinetic-energy store of a mass m moving at speed v is E_K=½mv². It is a scalar and is never negative.
Use speed magnitude and consistent units; doubling speed quadruples kinetic energy, while doubling mass doubles it.
A 4.0 kg trolley moving at 3.0 m s⁻¹ has kinetic energy 18 J.
Kinetic energy does not carry the direction sign of momentum, and stopping does not destroy it—it transfers it to other stores.
ConceptA-Level CAIE Physics AS