| CIRCUM-STANCES for man-made object of at least two kilograms | experimentally verified MAXIMUM-SPEED |
| in the air at sea-level (f.i. a car or a TGV-train) | 600km/h |
| in the air at a height of 10km (f.i. an airplane) | 1.000km/h |
| compared to the ground of the equator (f.i. a concord-airplane) | 1.000km/h + 40.000km/24h=2.666km/h |
| in an airless tube (railgun) | 15.000km/h |
| - - - - - - - - - - - - - - - - - | - - - - - - - - - |
| velocity NEEDED for space-travel around the earth at a height of 300km | 28.000km/h |