Question

3) Usain Bolt holds the men’s world record in both the 100 meter (9.58 seconds) and the 200 meter (19.19 seconds). Tyson Gay’s time in the 100 meter was 9.69 seconds. The women’s world record in both the 100 meter (10.49 seconds) and the 200 meter (21.34 seconds) is held by Florence Griffith-Joyner, “Flo Jo”. Answer the following questions.
What are all three sprinters times in kilometers per hour? Round your answers to the nearest tenths.
What are all three sprinters times in feet per second? 1 meter = 3.28084 feet. Round your answer to the nearest hundredths.
How much faster was Usain Bolt in the 100 meter than Tyson Gay?

Answer 1

We know that

1 km-------------> 1000 m
 X-----------------> 1 m
X=1/1000--------> 0.001 km

1 hour---------> 3600 sec
 X---------------> 1 sec
X=1/3600--------> 0.0002777 hour

1 ft-----------> 0.3048 m
X-----------> 1 m
X=1/0.3048 ----------> 3.28084 ft

Part 1) What are all three sprinters times in kilometers per hour? Round your answers to the nearest tenths. 

a) Usain Bolt  9.58 sec  in 100 meter
100 meter-----------> 100*0.001------> 0.10 km
9.58 sec-------------> 9.58*(1/3600)-----> 0.0026611 hour

0.10/0.0026611----------> 37.6 km/hour

b) Tyson Gay  9.69 sec  in 100 meter
100 meter-----------> 100*0.001------> 0.10 km
9.69 sec-------------> 9.69*(1/3600)-----> 0.0026916 hour

0.10/0.0026916----------> 37.2 km/hour

c) Florence Griffith-Joyner  10.49 sec  in 100 meter
100 meter-----------> 100*0.001------> 0.10 km
10.49 sec-------------> 10.49*(1/3600)-----> 0.0029138 hour

0.10/0.0029138----------> 34.3 km/hour

Part 2) What are all three sprinters times in feet per second?

a) Usain Bolt  9.58 sec  in 100 meter
100 meter-----------> 100*3.28084------> 328.084 ft
328.084 ft/9.58 sec----------> 34.25 ft/sec

b) Tyson Gay  9.69 sec  in 100 meter
100 meter-----------> 100*3.28084------> 328.084 ft
328.084 ft/9.69 sec----------> 33.86 ft/sec

c) Florence Griffith-Joyner  10.49 sec  in 100 meter
100 meter-----------> 100*3.28084------> 328.084 ft
328.084 ft/10.49 sec----------> 31.28 ft/sec

Part 3) How much faster was Usain Bolt in the 100 meter than Tyson Gay?
9.69-9.58-------> 0.11 sec

Usain Bolt  was 0.11 sec faster than Tyson Gay in the 100 meter