# Kinetic Energy Calculator

Calculate kinetic energy with KE = ½mv². Enter mass and velocity to find the energy of a moving object in Joules. Free physics calculator.

## What this calculates

Kinetic energy is the energy an object possesses due to its motion. Defined by the equation KE = ½mv², it depends on both the mass and the square of the velocity of the moving object. This means doubling the speed quadruples the kinetic energy, which is why high-speed collisions are so much more destructive than low-speed ones.

## Inputs

- **Mass** (kg) — min 0
- **Velocity** (m/s) — min 0

## Outputs

- **Kinetic Energy** (J) — Energy in Joules
- **Kinetic Energy** (kJ) — Energy in kilojoules

## Details

The kinetic energy formula KE = ½mv² is derived from the work-energy theorem. It tells us the amount of work needed to accelerate an object from rest to a given velocity, or equivalently, the work the object can do while decelerating to a stop.

  - KE is measured in Joules (J), where 1 J = 1 kg·m²/s²

  - m is the mass of the object in kilograms

  - v is the speed of the object in meters per second

Examples: A 0.145 kg baseball thrown at 40 m/s has a kinetic energy of about 116 J. A 1,200 kg car traveling at 27 m/s (about 60 mph) carries approximately 437,400 J (437.4 kJ) of kinetic energy.

The quadratic dependence on velocity is critically important in safety engineering, vehicle design, and ballistics. It also explains why braking distance increases with the square of speed.

## Frequently Asked Questions

**Q: What is kinetic energy?**

A: Kinetic energy is the energy an object has because of its motion. Any object that has mass and is moving possesses kinetic energy, calculated as KE = ½mv².

**Q: Why does kinetic energy depend on velocity squared?**

A: Because the work needed to accelerate an object increases with speed. Each additional unit of velocity requires more work (force over distance) than the previous one, leading to a quadratic relationship.

**Q: What is the difference between kinetic and potential energy?**

A: Kinetic energy is energy of motion. Potential energy is stored energy due to position or configuration (e.g., gravitational potential energy = mgh). Together they make up an object's mechanical energy.

**Q: Can kinetic energy be negative?**

A: No. Since mass is always positive and velocity is squared, kinetic energy is always zero or positive. An object at rest has zero kinetic energy.

**Q: How is kinetic energy related to momentum?**

A: Kinetic energy and momentum are related by KE = p²/(2m), where p is momentum. While momentum is a vector (has direction), kinetic energy is a scalar (no direction).

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Source: https://vastcalc.com/calculators/physics/kinetic-energy
Category: Physics
Last updated: 2026-04-21