Collision Calculator (1D, Elastic and Inelastic)
Two objects collide along a line. What happens to their velocities?
Your numbers
Your results
Collision Calculator (1D, Elastic and Inelastic) by TheCalcTools
How the Collision Calculator (1D, Elastic and Inelastic) works
Enter the mass and velocity of each object, using signs for direction.
Momentum is conserved in both cases.
In an elastic collision kinetic energy is also conserved; in a perfectly inelastic collision the objects stick together.
The formula
Worked example
Using the default values shown in the calculator:
| Mass 1 (kg) | 2 |
|---|---|
| Velocity 1 (m/s) | 3 |
| Mass 2 (kg) | 1 |
| Velocity 2 (m/s) | 0 |
- A 2 kg mass at 3 m/s hits a 1 kg mass at rest.
- Elastic: v₁′ = 1.00 m/s and v₂′ = 4.00 m/s.
- If they stick together they move at 2.00 m/s and lose 3.00 J of kinetic energy.
Result:
| Elastic: final velocity 1 (m/s) | 1.000 |
|---|---|
| Elastic: final velocity 2 (m/s) | 4.000 |
| Inelastic: common velocity (m/s) | 2.000 |
| Kinetic energy lost if inelastic (J) | 3.000 |
| Total momentum (kg·m/s) | 6.000 |
Frequently asked questions
What is conserved in a collision?
Total momentum always, if no external forces act. Kinetic energy is conserved only in an elastic collision.
What does a negative velocity mean?
The object moves in the opposite direction to the one you chose as positive.
Sources and further reading
Related calculators
More in Physics · All calculators
This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.