Question

In 2009, usain bolt of jamaica set a world record of 9.58 s in the 100-m dash. what was his average speed? give your answer in kilometers per hour.

Answer 1

Using a calculator, we find that Usain Bolt's average speed over the 100 meter race was about 23.2 miles per hour. Note that some of the numbers in this calculation, namely 100, 3600, and 5280 are exact while 3.28 and 9.63 are only approximate. Since the approximate numbers only have 3 significant digits we only report three digits in the final answer.