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).
Lockheed Martin says itâs developing a Mach 6 aircraft that would be faster than any other fighter jet. Called the Hypersonic Test Vehicle 3X, or HTV-3X, the new plane could reach speeds of more than six times the typical cruising speed of the Boeing 747-8, which has been chosen as the next presidential aircraft.