Edexcel IGCSE Physics 复习笔记 4.2.3 Kinetic Energy

• The kinetic energy (KE) of an object (also known as its kinetic store) is defined as:

The energy an object has as a result of its mass and speed

• This means that any object in motion has kinetic energy

• Kinetic energy can be calculated using the equation:

KE = ½ × m × v²

• Where:
  • KE = kinetic energy in Joules (J)
  • m = mass of the object in kilograms (kg)
  • v = speed of the object in metres per second (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

KE = ½ mv²

Step 3: Calculate the kinetic energy

KE = ½ × 1200 × (27)² = 437 400 J

Step 4: Round the final answer to 2 significant figures

KE = 440 000 J

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