20 °C = 293  kelvin . Muzzle velocity  of an  AK47   assault rifle   bullet 7102,3302,6001600Official  flight airspeed record 9803,2153,5302,194 Space shuttle  on re-entry7,80025,60028,00017,500 Escape velocity  on Earth11,20036,70040,00025,00011.2 km∙s−1Average orbital speed of planet  Earth 29,78397,713107,21866,623 Speed of light  in  vacuum  (symbol  c )299,792,458983,571,0561,079,252,848670,616,629Exactly 299,792,458 m∙s−1, by definition of the  meter .Vehicles often