Kinetic Energy

• What is kinetic energy?

  Kinetic energy is the energy stored in moving objects.
• Why does a stationary object have no kinetic energy?

  A stationary object has no kinetic energy because it is not moving.
• How is kinetic energy calculated?

  • Kinetic energy (in Joules) = 0.5 × mass (in kg) × speed (in m/s)²
• What is the unit of speed used in the kinetic energy equation?

  Metres per second (m/s).
• Is the kinetic energy equation provided in exams?

  No, students must learn it.
• If a car has a mass of 700 kg and is moving at a speed of 20 m/s, what is its kinetic energy?

  140,000 Joules.
• How is kinetic energy often converted for convenience?

  Kinetic energy is often converted from Joules to kilojoules by dividing by 1,000.
• Calculate the kinetic energy of a cyclist and bike with a total mass of 100 kg moving at 15 m/s.

  11,250 Joules.
• What is the kinetic energy of the cyclist and bike in kilojoules?

  11.25 kilojoules.
• If a tennis ball has a kinetic energy of 75 Joules and is traveling at 50 m/s, how do you calculate its mass?

  Mass = 0.06 kg.
• What energy transformation occurs in a car's engine when it runs on petrol?

  • Chemical energy from petrol is converted to kinetic energy as the car moves.