In dry air at NUMBER@1 ° C -LRB- NUMBER@2 ° F -RRB- , the threshold value required for an object to be traveling at a supersonic speed is approximately NUMBER@3 m/s , -LRB- NUMBER@4 ft/s , NUMBER@5 mph or NUMBER@6 km/h -RRB- .

At a typical temperature like NUMBER@7 degrees Fahrenheit -LRB- NUMBER@8 ° C -RRB- , the threshold value required for an object to be traveling at a supersonic speed is approximately NUMBER@9 m/s , NUMBER@10 ft/s , NUMBER@11 mph or NUMBER@12 km/h .
