At the 1988 Summer Olympics in
Seoul, South Korea, Florence Griffith-Joyner ran the
100-meter dash in 10.49 seconds (a world record). What
was her speed in miles per hour? (1 meter is approximately
39.37 inches.)
1 inch = 2.54 cm exactly
So 1 mile/h
= 1760 yds * 3 ft * 12 in. * 0.0254 m / 3600 s.
= 0.44704 m/s
so
100m/10.49s
=(100/10.49)/0.44704 mph
= ? mph
21.32 mph
To find Florence Griffith-Joyner's speed in miles per hour, we first need to convert the distance she ran in meters to inches and then convert the time she took to seconds.
1 meter is approximately 39.37 inches. So, we can multiply the distance run in meters by 39.37 to get the distance in inches.
Distance in inches = 100 meters * 39.37 inches/meter = 3937 inches
Now, let's convert the time from seconds to hours. There are 60 seconds in a minute, and 60 minutes in an hour. So, we divide the time in seconds by 60^2 (3600) to get the time in hours.
Time in hours = 10.49 seconds / 3600 seconds/hour = 0.002913 hours
Finally, to find the speed in miles per hour, we need to convert the distance in inches to miles. There are 12 inches in a foot and 5280 feet in a mile. So, we divide the distance in inches by (12 * 5280) to get the distance in miles.
Distance in miles = 3937 inches / (12 * 5280 inches/mile) = 0.062536 miles
Now, we can calculate the speed in miles per hour by dividing the distance in miles by the time in hours.
Speed in miles per hour = 0.062536 miles / 0.002913 hours ≈ 21.47 miles per hour
Therefore, Florence Griffith-Joyner's speed in miles per hour was approximately 21.47 miles per hour.