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.
Cruise is at 0.78 to 0.79 mach depending on the fuel consumption rate. Mach is the speed of sound and varies by altitude, temperature and air density. At 35,000 feet altitude, mach 1 is 663.5 mph for standard conditions. It is a few mph faster for lower altitudes and a few mph slower for higher altitudes. For standard conditions in the 33,000 to 39,000 typical cruise altitude, 0.78 to 0.79 mach would be 515 to 525 mph.