how fast is the tip of a whip
Whipcracking Recently, an additional, purely geometrical factor was recognized: the tip of the whip moves twice as fast at the loop of the whip, just like the top of a car's wheel moves twice as fast as the car itself.[2][3]
United States Army Air Assault School Soldiers will conduct two rappels on the wall side of the school's 34-foot (10 m) tower, 9 to 12 rappels from the open side, and two additional rappels from a UH-60 Blackhawk helicopter hovering at 21-27 m (70–90 ft). All rappels are conducted with and without combat equipment. During fast rope familiarization, students conduct a controlled descent and a static hold for five seconds. Students that successfully conduct both descents from a 12-foot (3.7 m) platform then descend from the 34-foot (10 m) tower using the stack-out/rapid exit technique. Fast rope descents are conducted without combat equipment. Soldiers are tested on: