Kinetic Energy (CIE IGCSE Physics)
Revision Note
Author
LeanderExpertise
Physics
Kinetic Energy
EXTENDED
- Energy in an object's kinetic store is defined as:
The amount of energy an object has as a result of its mass and speed
- This means that any object in motion has energy in its kinetic energy store
- Kinetic energy can be calculated using the equation:
EK = ½ × m × v2
- Where:
- EK = kinetic energy in joules (J)
- m = mass of the object in kilograms (kg)
- v = speed of the object in metres per second (m/s)
Worked example
Calculate the kinetic energy stored in a vehicle of mass 1200 kg moving at a speed of 27 m/s.
Step 1: List the known quantities
-
- Mass of the vehicle, m = 1200 kg
- Speed of the vehicle, v = 27 m/s
Step 2: Write down the equation for kinetic energy
EK = ½ mv2
Step 3: Calculate the kinetic energy
EK = ½ × 1200 × (27)2
EK = 437 400 J
Step 4: Round the final answer to 2 significant figures
EK = 440 000 J
Exam Tip
When performing calculations using the kinetic energy equation, always double-check that you have squared the speed. Forgetting to do this is the most common mistake that students make.
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