Impact Energy Calculator
Free calculate kinetic energy at impact from mass and velocity. determine impact force and collision energy.
Input Parameters
Results
Enter mass and velocity to calculate
What is Impact Energy?
Impact energy is the kinetic energy possessed by an object at the moment of impact or collision. It represents the energy that will be transferred during the collision.
Impact energy is calculated using the kinetic energy formula: E = ½mv², where m is mass and v is velocity. This energy determines the damage potential, deformation, and force generated during impacts.
Understanding impact energy is crucial in automotive safety (crash testing), sports equipment design, material testing, and engineering applications involving collisions.
Impact Energy Formula
Where:
- • E = Impact energy (J)
- • m = Mass (kg)
- • v = Velocity (m/s)
Note: Velocity is squared, so doubling velocity quadruples impact energy!
How to Calculate Impact 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 E = ½ × m × v²
Practical Examples
Example 1: Falling Object
A 2 kg object falls and hits the ground at 5 m/s. Calculate impact energy.
Solution:
E = ½ × m × v² = ½ × 2 kg × (5 m/s)²
E = ½ × 2 × 25 = 25 J
Impact energy = 25 Joules
Example 2: Vehicle Impact
A 1500 kg car traveling at 60 km/h impacts a barrier. Calculate impact energy.
Solution:
v = 60 km/h = 16.67 m/s
E = ½ × 1500 kg × (16.67 m/s)²
E = 208,333 J = 208.3 kJ
Applications
Automotive Safety
Crash testing, airbag design, and understanding collision forces for vehicle safety systems.
Protective Equipment
Designing helmets, padding, and safety gear to absorb and dissipate impact energy.
Material Testing
Impact testing (Charpy, Izod) to determine material toughness and resistance to sudden loads.
Sports Engineering
Understanding ball impacts, equipment design, and injury prevention in sports.
Frequently Asked Questions
Why is velocity squared in the formula?
Kinetic energy depends on velocity squared because work done to accelerate an object increases quadratically with speed. Doubling velocity requires 4× the energy.
Is impact energy the same as impact force?
No. Impact energy is the total energy transferred. Impact force depends on how quickly the energy is transferred (F = ΔE/Δt). Shorter collision times mean higher forces.
What happens to impact energy during collision?
Impact energy is converted to other forms: deformation, heat, sound, and sometimes kinetic energy of other objects. Some energy may be lost to the environment.
How does stopping distance affect impact?
Longer stopping distances reduce impact force by spreading the energy transfer over more time. This is why crumple zones in cars reduce injury.
Can impact energy be negative?
No, kinetic energy is always positive (mass and velocity² are always positive). However, the change in energy during a collision can be negative if the object slows down.