How fast can cheetahs run when they try to catch there prey?

The speed of a hunting cheetah averages 64 km/h (40 mph) during a chase, interspersed with a few short bursts when the speed may vary between 104 and 120 km/h (65 and 75 mph); the most reliable measurement of the typical speed during a short chase is 112 km/h (70 mph). Cheetahs have little endurance and can not run at top speed for an extended period.

70 miles per hour