If you are driving 65 mph, how many feet per second are you driving? Round to nearest tenth please

Question

I need help with this word problem.

Answer 1

65 mph means in 1 hour you drive 65 miles.

 

To find out how many feet you drive in 1 second you need to convert the above in terms of feet and secs

 

1 hour = 60  minutes and  1 minute has 60 secs

So 1 hour has 60* 60 secs = 3600 secs.

 

1 mile - 5280 feet

65 miles = 65*5280 feet

 

So in 3600 secs you are driving 65 * 5280 feet

 

or in 1 sec you can drive (65 * 5280)/3600

 which is equal to 95.33 ft 

 

or you are driving at 95.33 ft/sec

 

Answer 2

1. this is called dimensional analysis

2. 1 mi = 5280 ft

3. 1 hr = 60 min 

4. 1 min = 60 sec

5. therefore,

 

65 mi/ 1 hr * (1 hr/60 min) * (1 min/60 sec) = 65 mi/ (60*60) sec = 65 mi/3600 sec

65 mi/3600 sec * 5280 ft/1 mi = (65*5280) ft/3600 sec = 343200 ft/3600 sec = 3432 ft/36 sec ≈ 95.3 ft/sec