Weight loss. If your cat is overweight, you will want to feed for 2 pounds less, or 40 fewer calories a day, and readjust every time your cat loses a pound, until you hit a healthy weight, and then maintain.  Differences in metabolism.
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.
Mach number (Ma or M) is the speed of an object moving in air, divided by the speed of sound at that particular conditions, including temperature and pressure. At Standard Sea Level and temperature 15 degrees Celsius, the speed of sound is 761.2 miles per hour (mph) = 340.3 meters per second (m/s) = 1225 km/h = 1116 foot per second (ft/s) = 661.5 knots (kn, kt or kts).