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Kinetic energy

Kinetic energy is the energy which makes objects move or vibrate.

If we know the:

  • mass of the object, in kilograms,
  • speed of the object, in metres per second,

…then we can calculate the amount of kinetic energy it has!

The formula we use is:

If we put it into symbols, we get:

Where:

  • is the kinetic energy, in joules,
  • is the mass of the object, in kilograms,
  • is the speed of the object, in metres per second,

A car has a mass of 1000 kg and is moving at a speed of 20 m/s. What is its kinetic energy?

Section titled “A car has a mass of 1000 kg and is moving at a speed of 20 m/s. What is its kinetic energy?”

A cyclist has a kinetic energy of 1400 J and is moving at a speed of 7 m/s. What is the mass of the cyclist?

Section titled “A cyclist has a kinetic energy of 1400 J and is moving at a speed of 7 m/s. What is the mass of the cyclist?”

A ball has a kinetic energy of 50 J and a mass of 0.5 kg. What is the speed of the ball?

Section titled “A ball has a kinetic energy of 50 J and a mass of 0.5 kg. What is the speed of the ball?”