Kinetic Energy (GCSE Physics)
Kinetic Energy
Kinetic Energy, KE
Moving objects have kinetic energy.
Kinetic energy depends on both the speed and mass of the object.
- If two objects have the same speed, the heavier object has more kinetic energy.
- If two objects have the same mass, then the faster moving object has more kinetic energy.
Calculating KE
The kinetic energy of an object can be calculated using the following equation:
Where:
- kinetic energy, Ek, in joules, J
- mass, m, in kilograms, kg
- speed, v, in metres per second, m/s
Examples: KE Calculations
Question: An armadillo of mass 500kg moves at 5m/s. What is its kinetic energy in kJ?
- Write out the equation for kinetic energy.
Put numbers that we already know into the equation.Kinetic energy = 0.5 x 500 x 52
Kinetic energy = 6,250 Joules
Normally, we would leave our answer in Joules, which is the standard unit to measure energy. However, this question has specifically asked us to give our answer in kJ.
Kinetic Energy = 6,250 Joules
Kinetic Energy = 6.25 kJ
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