## Matt6288 4 years ago I need a math wizard! What is wrong with the dimensional analysis work in the following problem in which 5 feet/second was converted to miles per hour?

1. Matt6288

5feet/second was converted to miles per hour? 5feet/1second*1mile/5280feet*1minute/60s… ≈ 0.0001 miles per hour.

2. Matt6288

A. In the first conversation ratio, the second should be on top and the feet should be on bottom. B. In the second conversation ratio, the feet should be on top and the mile should be on bottom. C. In the third conversion ratio, the seconds should be on top and the minutes should be on the bottom. D. In the fourth conversation ratio, the hour should be on top and the minutes should be on bottom.

3. amistre64

$\frac{ft}{sec}\frac{sec}{min}\frac{min}{hr}=\frac{ft}{hr}$ $\frac{ft}{hr}\frac{mile}{ft}=\frac{mile}{hr}$

4. amistre64

or some versions of that

5. amistre64

so the min/sec that they have is not a healthy operation

6. Matt6288

so it would be A?

7. amistre64

hard to tell, that last bit needs to be an sec/hr i believe

8. amistre64

5feet 1mile 1minute sec feet sec is what they got so feet are off the top and we got mile/sec we need sec/hr to finish up

9. amistre64

the third conversion ... hard to count them, is whats bad at any rate

10. amistre64

is ft/sec the 1st conversion or the is it not counted as a conversion?

11. amistre64

ok, it reads as the first; so C is your best pick. oy that was torture :)

12. Matt6288

Thx :)