Kinetic Energy Calculator
Inputs
Enter parameters to calculate Kinetic Energy, Mass, or Velocity.
What is Kinetic Energy?
Kinetic Energy (KE) is the energy that an object possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
Simply put, if something is moving, it has kinetic energy. The faster it moves or the heavier it is, the more kinetic energy it has.
The Kinetic Energy Formula
The classical mechanics formula for kinetic energy is:
KE = ½ × m × v²- KE = Kinetic Energy (Joules, J)
- m = Mass (Kilograms, kg)
- v = Velocity (meters per second, m/s)
Relationship with Velocity
Notice that velocity is squared in the formula. This means if you double the speed of an object, its kinetic energy increases by a factor of 4 (2²).
This is why car crashes at high speeds are exponentially more dangerous than those at lower speeds.
Examples
Example 1: Bowling Ball
A 5 kg bowling ball rolling at 4 m/s.
- Mass (m) = 5 kg
- Velocity (v) = 4 m/s
- KE = 0.5 × 5 × 4² = 0.5 × 5 × 16 = 40 Joules
Example 2: A Car
A 1,000 kg car moving at 20 m/s.
- Mass (m) = 1,000 kg
- Velocity (v) = 20 m/s
- KE = 0.5 × 1000 × 20² = 500 × 400 = 200,000 Joules (200 kJ)
Frequently Asked Questions
Can Kinetic Energy be negative?
No. Since mass is positive and velocity squared is always positive (or zero), Kinetic Energy is always non-negative.
What is the unit Joule?
A Joule (J) is the SI unit of energy. One Joule is equal to the work done by a force of one Newton acting through one meter.
Does direction matter?
No. Kinetic energy is a scalar quantity. It depends only on the speed (magnitude of velocity), not the direction.