Enter the initial position, final position, and time into the calculator to determine the constant velocity.
- All Physics Calculators
- All Velocity Calculators
- Final Velocity Calculator
- Maximum Velocity Calculator
- Velocity Calculator
- Initial Velocity Calculator
- Acceleration Calculator
Constant Velocity Formula
Constant velocity motion means the object covers equal displacements in equal time intervals. The calculator uses one base relationship and rearranges it for each mode.
v = Δx / t
Δx = v * t
t = Δx / v
x = x₀ + v * t
- v = constant velocity
- Δx = displacement (change in position)
- t = elapsed time
- x₀ = initial position
- x = final position
The four calculator modes map to the four equations above. The Velocity mode divides displacement by time. The Distance mode multiplies velocity by time. The Time mode divides displacement by velocity. The Final Position mode adds the displacement (v × t) to the initial position x₀, so a negative velocity produces a final position behind the start.
Reference Values and Unit Conversions
Use these tables to sanity check inputs and outputs.
| Motion | m/s | km/h | mph |
|---|---|---|---|
| Walking | 1.4 | 5.0 | 3.1 |
| Jogging | 3.0 | 10.8 | 6.7 |
| City driving | 13.4 | 48.3 | 30 |
| Highway | 29.1 | 104.6 | 65 |
| Speed of sound (air) | 343 | 1235 | 767 |
| Convert | Multiply by |
|---|---|
| m/s to km/h | 3.6 |
| m/s to mph | 2.2369 |
| mph to m/s | 0.44704 |
| ft/s to m/s | 0.3048 |
| mi to km | 1.6093 |
Worked Examples
Example 1: Find velocity. A train covers 480 m in 24 s at constant velocity. Using v = Δx / t, v = 480 / 24 = 20 m/s. That converts to 72 km/h.
Example 2: Find final position. A cyclist starts at x₀ = 50 m moving at v = -4 m/s for t = 10 s. Using x = x₀ + v × t, x = 50 + (-4)(10) = 10 m. The negative velocity moved the cyclist 40 m back along the axis.
FAQ
Is constant velocity the same as constant speed? No. Constant velocity requires constant speed and constant direction. A car going around a curve at 30 mph has constant speed but changing velocity.
What if acceleration is not zero? These formulas do not apply. Use kinematic equations that include acceleration, such as Δx = v₀t + ½at².
Why does the time mode reject zero velocity? Dividing by zero is undefined. An object with zero velocity does not cover any distance, so no finite time produces a nonzero displacement.
Can displacement be negative? Yes. A negative sign indicates motion opposite to the chosen positive direction. The calculator preserves the sign through all four modes.
