gal
Accelerationexact by definition
The gal is exactly 1 cm/s², 0.01 m/s². It is the unit of gravimetry and of strong-motion seismology: Earth's surface gravity is about 980 gal, and peak ground acceleration in an earthquake record is reported in gal or in fractions of g.
Watch out: It is not the gallon, and the symbol is capitalised Gal to keep them apart. Note also that gravity anomalies are almost never quoted in gal itself; the practical unit is the milligal, and the microgal for absolute gravimeters.
| 1 | 0.01 |
Named for Galileo, who established that bodies fall with constant acceleration. It is a CGS unit that survived the move to SI purely because the numbers come out conveniently sized for the field, and because everything ever published in geodesy uses it.
One gal in every acceleration unit
| 1,000,000 | microgal (μGal) | |
| 1,000 | milligal (mGal) | |
| 10 | millimeter per second squared (mm/s²) | |
| 1 | centimeter per second squared (cm/s²) | |
| 1 | gal (Gal)this unit | |
| 0.393701 | inch per second squared (in/s²) | |
| 0.036 | kilometer per hour per second (km/h/s) | |
| 0.0328084 | foot per second squared (ft/s²) | |
| 0.0223694 | mile per hour per second (mph/s) | |
| 0.01 | meter per second squared (m/s²) | |
| 0.00101972 | standard gravity (g) |