Question

Which expression is true?

:A. 50 kilometers/hour > 139 centimeters/second
B. 50 kilometers/hour < 139 centimeters/second
C. 50 kilometers/hour = 139 centimeters/second
D. cannot be determined

Answer 1

You need to convert km/h to cm/s

Answer 2

how do i do that?

Answer 3

You need to start with basic unit conversions.

Do you know how many cm are in a km?
If not, then do you know how many m are in a km, and how many cm are in a m?
Also, how many seconds are in an hour?
If you don't know that, then how many seconds are in a minute, and how many minutes are in an hour?

Answer 4

Kilometer = 1000 meters
1 meter = 100 centimeters
1 hour = 60 minutes
1 minute = 60 seconds .....
is it A

Answer 5

Ok, your conversions are correct.
Now we convert:

\(50 \dfrac{km}{h} \times \dfrac{1000 ~m}{1 ~km} \times \dfrac{100~cm}{1~m}
\times \dfrac{1~h}{60~mn} \times \dfrac{1~mn}{60~s} \)

Notice that all units cancel out except cm/s.
Just multiply out the numbers.

Answer 6

i think i did it right so it should be A right?

Answer 7

Yes. I got 50 km/h = 1388.888... cm/s, so 50 km/h > 139 cm/s.