Mach and Mile Mathematics with the X15
Exercise 1 Key
1: 354,200 feet/5,280 feet/mile = 67.08 miles
2: 354,200 feet  45,000 feet = 309,200 feet
3: 309,000 feet / 5,280 feet/mile = 58.6 miles
4: answers will vary
5: 4,520 miles/hour  4,486 miles/hour = 34 miles/hour
6: 4,520 miles per hour / 65 miles per hour = 69.5
times faster!
7: 762 miles/ hour  87 miles/ hour = 675 miles/hour
8: 4,520 miles hour / 675 miles/hour = Mach 6.7
9: 6.7 times the speed of sound
Exercise 2 Key
1: 65 miles/hour / 762 miles/hour* = Mach .085
*from table
2: from table: for altitude range of 20,000 30,000
feet, the speed of sound in the stated air conditions is 693 miles/hour.
When the pilot is flying at Mach 1, he/she is flying at the speed of sound,
or 693 miles/hour.
3: 762 miles/hour at sea level  693 miles/ hour
at 29,028 feet = 69 miles/hour
4: 354,200 feet  29,028 feet = 325,172 feet
325,172 feet / 5,280 feet = 61.6 miles
answers will vary
5: 3,111 miles/hour / 662 miles/hour = Mach 4.7
6: 15 miles per hour / 762 miles per hour = Mach
.02
That'9s two onehundredths of the speed of sound!
Mach .02 X 693 miles/hour = 13.86 miles/ hour
