Kinetic energy measures how much work it took to bring a moving object to its current speed — or how much damage it can do in a collision.
About this calculator
Kinetic energy measures how much work it took to bring a moving object to its current speed — or how much damage it can do in a collision. This calculator uses KE = ½mv² with mass in kg and velocity in m/s.
Example: a 2 kg ball at 10 m/s has KE = ½ × 2 × 100 = 100 J. At 20 m/s the same ball has 400 J — four times as much because velocity is squared.
Compare moving energy with stored energy using the [[gravitational-potential-energy]] calculator (PE = mgh). The [[work]] calculator shows energy transferred by a force over distance. Find speed first with the [[speed-distance-time]] or [[velocity]] calculators, then plug velocity here. The [[momentum]] calculator uses the same mass and velocity but answers a different question — how hard the object is to stop.
Common uses
- Comparing KE before and after a speed change in homework
- Ballistics and sports science estimates
- Work–energy theorem problems in Class 11
- Checking collision energy in intro physics labs
- Seeing why highway crashes are far worse than city speeds
Frequently asked questions
What is the kinetic energy of a 2 kg object moving at 10 m/s?
KE = ½ × 2 × 10² = 100 J. Enter mass 2 and velocity 10. The calculator returns 100 joules.
Why does doubling speed quadruple kinetic energy?
KE depends on v². If v doubles, v² becomes four times larger. A car at 80 km/h has four times the KE of the same car at 40 km/h.
How is kinetic energy related to work?
The work–energy theorem says net work on an object equals its change in KE. Use the [[work]] calculator for W = Fs when a force acts over a distance.
Can kinetic energy be negative?
No. Mass is positive and v² is always non-negative, so KE ≥ 0. Direction of motion does not change the magnitude of kinetic energy.