Calculation Result
Formula and substitution
Step-by-step calculation
Force versus speed analysis
The chart changes with the selected calculation mode.
Scenario comparison
Compare forces, momentum, energy, and motion conditions.
| Scenario | Mode | Mass | Initial speed | Final speed | Force | Momentum change | Kinetic energy |
|---|
Calculation history
Recent calculations stay in this browser until cleared.
| Time | Mode | Mass | Speed change | Force | Acceleration | Impulse | Energy |
|---|
Export and copy
Copy the current report or save useful records. Exported values include units. Print creates a clean PDF through your browser.
Formula used
Linear motion
- Force from acceleration: F = m × a
- Acceleration from speed change: a = (v₂ − v₁) ÷ t
- Stopping distance method: a = (v₂² − v₁²) ÷ (2d)
- Momentum: p = m × v
- Impulse: J = Δp = F × t
Energy and circular motion
- Centripetal force: F = m × v² ÷ r
- Kinetic energy: KE = ½ × m × v²
- Average power during change: P = ΔKE ÷ t
- Turning acceleration: a = v² ÷ r
- Force direction follows the selected sign convention.
How to use
- Select the motion method matching your known values.
- Enter mass and every required motion quantity.
- Choose units before starting the calculation.
- Select precision, notation, and output force units.
- Press calculate to view results and detailed steps.
- Add the result to compare another scenario.
Mass and speed alone do not determine force. Another motion condition is always required. Use acceleration, time, distance, or turning radius.
Example data
| Example | Mass | Motion data | Formula | Approximate result |
|---|---|---|---|---|
| Car braking | 1,200 kg | 72 km/h to rest in 4 s | F = m(v₂ − v₁)/t | −6,000 N |
| Runner start | 75 kg | 0 to 8 m/s in 2 s | F = m(v₂ − v₁)/t | 300 N |
| Vehicle turn | 1,000 kg | 15 m/s, 30 m radius | F = mv²/r | 7,500 N |
| Ball impact | 0.45 kg | 20 m/s to −10 m/s in 0.02 s | F = mΔv/t | −675 N |
Assumptions and limitations
The calculator uses idealised average force equations. Real impacts may create much larger peak forces. Material deformation and friction can change actual results.
Constant acceleration is assumed for time and distance modes. Circular motion assumes a constant radius and speed. Engineering decisions require measured data and professional review.
Frequently asked questions
1. Can force be calculated from mass and speed alone?
No. Force describes how momentum changes with time. You also need acceleration, time, distance, or radius.
2. Why can braking force appear negative?
A negative sign indicates force opposite the chosen positive direction. Its magnitude still shows the average braking strength.
3. Is collision force exact?
No. The result is an average across the entered collision time. Peak impact force can be considerably higher.
4. What is the difference between force and momentum?
Momentum equals mass multiplied by velocity. Force measures the rate at which that momentum changes.
5. Why does speed greatly affect turning force?
Centripetal force depends on speed squared. Doubling speed creates four times the required inward force.
6. Which force unit should I use?
Newtons are standard in SI calculations. Pound-force and kilogram-force remain useful for familiar engineering contexts.
7. What does impulse represent?
Impulse equals the change in momentum. It also equals average force multiplied by the interaction time.
8. Can the calculator find a missing variable?
Yes. Reverse mode can find mass, acceleration, time, final speed, stopping distance, or turning radius.
9. Does the calculator include air resistance?
No. Standard modes use simplified mechanical relationships. Add measured external forces when higher accuracy is required.