Kinetic Energy Calculator
Free calculate kinetic energy from mass and velocity using ke = ½mv². Get instant, accurate results with our easy-to-use calculator.
Input Parameters
Results
Enter mass and velocity to calculate
What is Kinetic Energy?
Kinetic energy is the energy an object possesses due to its motion. It depends on both the object's mass and its velocity, with velocity having a squared relationship.
The faster an object moves or the more massive it is, the more kinetic energy it has. Kinetic energy is a scalar quantity (no direction) and is always positive. It's measured in Joules (J) in the SI system.
Kinetic energy is fundamental in understanding collisions, work-energy theorem, and the behavior of moving objects. It's converted to other forms of energy during impacts, braking, and other processes.
Kinetic Energy Formula
Where:
- • KE = Kinetic energy (J)
- • m = Mass (kg)
- • v = Velocity (m/s)
Note: Velocity is squared, so doubling velocity quadruples kinetic energy!
How to Calculate Kinetic Energy
-
1
Convert mass to kilograms
Convert all mass units to kg for consistent calculations.
-
2
Convert velocity to m/s
Convert km/h or mph to meters per second (1 km/h = 0.2778 m/s, 1 mph = 0.447 m/s).
-
3
Apply the formula
Calculate KE = ½ × m × v²
Practical Examples
Example 1: Moving Car
A 1500 kg car travels at 60 km/h. Calculate its kinetic energy.
Solution:
v = 60 km/h = 16.67 m/s
KE = ½ × 1500 kg × (16.67 m/s)²
KE = 208,333 J = 208.3 kJ
Example 2: Baseball
A 0.145 kg baseball is thrown at 40 m/s. What is its kinetic energy?
Solution:
KE = ½ × 0.145 kg × (40 m/s)²
KE = 116 J
Applications
Automotive
Understanding braking distance, crash energy, and vehicle safety design based on kinetic energy.
Sports
Analyzing ball speeds, impact forces, and understanding energy transfer in sports collisions.
Aerospace
Calculating orbital energy, re-entry speeds, and understanding spacecraft motion and collisions.
Engineering
Designing safety systems, understanding impact forces, and analyzing mechanical systems.
Frequently Asked Questions
Why is velocity squared in the formula?
Kinetic energy comes from work done to accelerate an object. Work = force × distance, and since distance depends on velocity² (from kinematics), kinetic energy is proportional to v².
Can kinetic energy be negative?
No, kinetic energy is always positive or zero. Since it depends on v² (which is always positive), and mass is always positive, KE ≥ 0.
What happens to kinetic energy in collisions?
In elastic collisions, kinetic energy is conserved. In inelastic collisions, some kinetic energy is converted to other forms (heat, deformation, sound).
How does kinetic energy relate to work?
The work-energy theorem states: W = ΔKE. Work done on an object equals its change in kinetic energy. This connects forces and motion.
What is the difference between kinetic and potential energy?
Kinetic energy is energy of motion (KE = ½mv²). Potential energy is stored energy due to position (PE = mgh for gravity). They can convert between each other.