# Delivery Systems

### Questions:

- An ICBM reenters the earth's atmosphere at Mach 25. This means that it is traveling 25 times the speed of sound at sea level (Mach 1), which is about 1100 ft/s. What is the velocity of the missile in miles per hour?
- Define CEP (Circular Error Probable).

### Answers:

- An ICBM reenters the earth's atmosphere at Mach 25. This means that it is traveling 25 times the speed
of sound at sea level (Mach 1), which is about 1100 ft/s. What is the velocity of the missile in miles per
hour?
25 Mach x (1100 ft/s per mach) = 27,500 ft/s

27,500 ft/s x 3,600 s/hr x 1/5,280 mi/ft = 18,750 mi/hr - Define CEP (Circular Error Probable).
The Circular Error Probable is a measurement of the radius of a circle around a target that 50% of the missiles will hit.