Physics
Impact speed from a fall
Setting the stored potential energy equal to the kinetic energy at the bottom cancels the mass, leaving the speed in terms of height alone.
The Formula
v = sqrt(2 x g x h)
Setting the stored potential energy equal to the kinetic energy at the bottom cancels the mass, leaving the speed in terms of height alone.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| v | Impact speed | m/s | Speed reached just before landing. |
| g | Gravitational acceleration | m/s^2 | About 9.80665 near the Earth's surface. |
| h | Height | m | Height the object fell from. |
What Each Symbol Means
vm/s
Impact speed
Speed reached just before landing.
gm/s^2
Gravitational acceleration
About 9.80665 near the Earth's surface.
hm
Height
Height the object fell from.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate potential energy page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Potential Energy, filed under Science. Every number the guide produces comes from substituting into this one line.