Optimally, Mach 2 is 1,552.4141 mph. This measurement is twice the speed of a moving object relative to the speed of sound in a surrounding medium when placed under ambient conditions. More » Science Measurements

The speed of light is about 670,616,629 mph, and one could travel round the earth 7 1/2 times in just a second with this speed. For another perspective, the average distance from the Earth to the Moon is 238,854 miles, a... More » Science Physics Motion & Mechanics

Knots are the unit of measurement that describes the speed of boats and airplanes. One knot is equal to roughly 1.151 miles per hour. With this conversion factor, 18 knots is equal to roughly 20.718 miles per hour. More » Science Measurements
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To convert from knots to miles per hour, multiply the speed in knots by the number of feet per knot, and divide by the number of feet per mile. The term "knot" refers to speed at sea and dates back to the use of a rope t... More » Science Measurements

To convert 60 knots to miles per hour, multiply 60 by 1.15. A knot is a unit of speed also known as a nautical mile. More » Science Measurements

It takes four hours to travel a distance of 100 miles at a constant speed of 25 miles per hour. The speed must be constant or at an average of 25 miles per hour for this to be true. More » Science Measurements

To convert 220 kilometers per hour to miles per hour, divide 220 by 1.61. The result shows that 220 kph equals about 136.65 mph. More » Science Measurements