ClarityHow to use this tool
- Enter vertical drop height in metres.
- Use the gravitational acceleration for your model; the default is 9.80665 m/s².
- Calculate impact speed and fall time for an object released from rest without air resistance.
Input reference and sample values
Use the units and choices shown for each field. Sample values are provided for practice, not as recommendations.
| Input | Format and units | Sample |
|---|---|---|
| Vertical height | Numeric value. Unit: m. Zero or positive. | 20 |
| Gravitational acceleration | Numeric value. Unit: m/s². Must be greater than zero. | 10 |
Result for these sample inputs
20 m/s
- Fall time (s)
- 2
- Speed (km/h)
- 72
Select Try the example in the form to load these values and calculate them again. This replaces the current form inputs. Compare the result with the method and worked explanation below.
The method, explained
Speed = √(2g × height).
For a 20 m drop with g = 10 m/s², speed is 20 m/s (72 km/h) and fall time is 2 seconds.
What to keep in mind
No initial velocity or aerodynamic drag is modeled. 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
Does object mass change this result?
Not in this ideal model. Air resistance and buoyancy can make real objects behave differently.
What if the object is thrown downward?
This tool assumes zero initial speed. Use a model that includes initial velocity for a thrown object.
Methodology maintained by ClarityKit. How these tools are built and checked.