Free · Physics models
Stopping Energy and Mean Force
Estimate kinetic energy and mean stopping force from a speed, mass and stopping distance or time.
- Formula & worked example
- Private in your browser
- No signup
Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
Energy (E) = 50.000000; Average force (F==a==) = 50.000000; Maximum force (F==max==) = 100.00000. The worked example lists its inputs and unit conventions.
E = mv²/2; Fmean = E/d or mv/Δt; Fpeak = 2Fmean for a triangular pulse.
Worked example
Enter these known values and leave the other values blank.
- Mass (m)
- 1 kg
- Velocity (v)
- 10 m/s
- Collision distance (d)
- 1 m
- Average force (F==a==)
- 50 N
- Maximum force (F==max==)
- 100 N
- Energy (E)
- 50 J
Assumptions and limitations
- The object is brought to rest and all translational kinetic energy is assigned to stopping work. The displayed doubled force assumes a triangular pulse; it is not a measured peak. Rebound, deformation dynamics and injury prediction are outside this model.
- Clear the quantity to solve an inverse; keep known quantities fixed with locks. Some inverses are singular or ambiguous and require further known values.
- Unit selectors convert the same physical quantity. Rounded reference constants and presets limit physical accuracy even when arithmetic displays more digits.
Common questions
What does this model assume?
The object is brought to rest and all translational kinetic energy is assigned to stopping work. The displayed doubled force assumes a triangular pulse; it is not a measured peak. Rebound, deformation dynamics and injury prediction are outside this model.
Can I solve for an input?
Editable calculated fields support the captured inverse relationships. Clear the unknown and supply enough independent known values; an inverse must remain within the declared physical domain.
References
The object is brought to rest and all translational kinetic energy is assigned to stopping work. The displayed doubled force assumes a triangular pulse; it is not a measured peak. Rebound, deformation dynamics and injury prediction are outside this model.