Z-line can refer to: 1  the borders that separate and link sarcomeres within a skeletal muscle. 2  a ban on a user's IP address for the purposes of blocking their access to Internet Relay Chat.3  the gastroesophageal junction that joins the esophagus to the stomach. 4  Z, a New York City Subway service.-line can refer to: 1  the borders that separate and link sarcomeres within a skeletal muscle. 2  a ban on a user's IP address for the purposes of blocking their access to Internet Relay Chat.
If we take another look at the Mach 1 vs. altitude tables already discussed, we see that the speed of sound at 30,000 ft is 678.2 miles per hour. All we have to do is multiply this value by 3 to determine the speed of a vehicle traveling Mach 3 at 30,000 ft in miles per hour. The answer is 2,035 mph.ach number: Mach number is a quantity that defines how quickly a vehicle travels with respect to the speed of sound. The Mach number (M) is simply the ratio of the vehicle's velocity (V) divided by the speed of sound at that altitude (a).
Since the speed of sound through the standard atmosphere is 761 mph (1,223 km/h) at sea level, Mach 2 then follows as 1,522 mph (2,447 km/h). If you were to ask how fast is Mach 2 at an altitude of 30,000 ft (9,150 m), we would use the same methodology to find out that it is only 1,356 mph (2,180 km/h) because the speed of sound generally decreases as altitude increases.