Ten and Ten When Coast Guard para rescue jumpers leap from a helicopter to save a person in the water, they like to jump when the helicopter is flying “ten and ten,” which means it is 10 feet above the water and moving forward with a speed of 10 knots. What is “ten and ten” in SI units? (A knot is one nautical mile per hour, where a nautical mile is 1.852 km.)
Answer:
The SI unit for distance is meter (m), and the SI unit for speed is meter per second (m/s). Therefore for given values, identify the equivalent values in SI units and convert them into SI units.
SI equivalent for 1 ft length is,
1ft = 0.3047 m
SI equivalent of 1 knot speed can be calculated as follows:
The SI equivalent for 10-ft height is,
The SI equivalent for 10-knot speed is,
Therefore, after rounding off to two significant figures, the SI equivalent of “ten and ten” is about 3.1 m and 5.1 m/s.