Usain Bolt holds the world record for the 100 m dash at 9.58 s. What was his average speed in miles/hour for this distance? The equivalence statements are 1 km = 0.621 mi and 3,600 s = 1 hr. It is interesting to compare this value with the average speed for walking (3 mph), bicycling (12 mph), and horse racing (38 mph).
A) 23.3 mi/hr
B) 46.6 mi/hr
C) 11.7 mi/hr
D) 18.7 mi/hr
E) 26.7 mi/hr

Question

Quizplus · Accepted Answer

Explanation:First, convert the distance to miles: 100 m * (1 km / 1000 m) * (0.621 mi / 1 km) = 0.0621 mi. Then, convert the time to hours: 9.58 s * (1 hr / 3600 s) = 0.00266 hr. Finally, calculate the average speed: 0.0621 mi / 0.00266 hr = 23.3 mi/hr.

Usain Bolt Holds the World Record for the 100 M