The physics
Kinetic energy is the energy of motion: half the mass times velocity squared. The squared term is the punchline — double your speed and you carry four times the energy, which must all go somewhere when you stop.
Kinetic energy of a 40,000 kg lorry at 80 km/h
Answer: kinetic energy = 9,876,543.2 J (in kilowatt-hours 2.74348 kWh).
What we know
- Mass: 40000 kg
- Velocity: 80 km/h = 22.22222222 m/s (converted to the unit the formula takes)
Step by step
- Given
- m = 40000 kg, v = 22.22222222 m/s
- Formula
- KE = ½ × m × v²
- Substitute
- KE = ½ × 40000 × 22.22222222²
- Result
- KE = 9,876,543.2 J
All results
| Kinetic energy | 9,876,543.2 J |
|---|---|
| In kilowatt-hours | 2.74348 kWh |
Open the kinetic energy calculator with these numbers → and change any of them.