kinetic energy

• What is kinetic energy?

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

  A stationary object has no kinetic energy because it is not moving.
• What is the equation to calculate kinetic energy?

  Kinetic energy in joules is given by the equation $KE =$$0.5 \times m \times v^2$.
• What units are used for mass and speed in the kinetic energy equation?

  Mass is in kilograms and speed is in meters per second.
• If a car has a mass of 700 kg and is moving at a speed of 20 m/s, what is its kinetic energy?

  The kinetic energy is 140,000 joules.
• How do scientists often convert joules into kilojoules?

  Scientists convert joules into kilojoules by dividing by 1,000.
• What is the kinetic energy of a cyclist and bike with a total mass of 100 kg moving at a speed of 15 m/s?

  The kinetic energy is 11,250 joules.
• If a tennis ball has a kinetic energy of 75 joules and is traveling at 50 m/s, how do you calculate its mass?

  The mass is calculated using the equation $m =$$\frac{KE}{0.5 \times v^2}$.
• What is the mass of a tennis ball with a kinetic energy of 75 joules traveling at 50 m/s?

  The mass is 0.06 kg.
• What steps should you follow to calculate kinetic energy for a moving object?

  1. Identify the mass of the object in kilograms.
  2. Identify the speed of the object in meters per second.
  3. Use the equation $KE =$$0.5 \times m \times v^2$ to calculate kinetic energy.
• What are the energy changes taking place in a car running on petrol?

  • The car runs on petrol, which is a store of chemical energy.
  • A chemical reaction occurs in the engine.
  • Some of the chemical energy is converted to kinetic energy as the car moves.