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Physics

Perfectly Inelastic Collision Calculator

Find common velocity and kinetic-energy loss when two objects stick together in one dimension.

SI units shown beside each fieldIdeal model explained below
Physics lab
Physics lab

Use the units beside each input and review the model assumptions.

See the method

Define your system

Runs on your device

Your calculated quantity

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter mass 1, velocity 1, mass 2, velocity 2.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Conservation of momentum gives vf=(m1v1+m2v2)/(m1+m2). Lost kinetic energy = ½[m1m2/(m1+m2)](v1−v2)².

A WORKED EXAMPLE

Using mass 1 = 2 kg, velocity 1 = 5 m/s, mass 2 = 3 kg, velocity 2 = 0 m/s, the result is 2 m/s. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

One-dimensional isolated system with objects sticking together. Use signed velocities along one common axis.

What to keep in mind

One-dimensional isolated system with objects sticking together. Use signed velocities along one common axis. An idealized educational model using the stated SI units. Real systems may need additional forces, losses or experimental measurements. Not a safety or equipment specification.

Common questions

How do I use this perfectly inelastic collision calculator?

Find common velocity and kinetic-energy loss when two objects stick together in one dimension. Enter mass 1 in kg, velocity 1 in m/s, mass 2 in kg, velocity 2 in m/s. The starting example is editable; use values for the same system or project.

Which assumptions affect this result?

One-dimensional isolated system with objects sticking together. Use signed velocities along one common axis.

Methodology maintained by ClarityKit. How these tools are built and checked.