Question

A car is traveling at a rate of 36 miles per hour. What is the car's rate in feet per second? How many feet will the car travel in 2 seconds? In your computations, use the fact that 1 mile is equal to 5280 feet. Do not round your answers.

Answer 1

@ehuman @phi @mathmale

Answer 2

can you change 36 miles to feet ?

Answer 3

i'm not sure

Answer 4

you want to multiply
\[ \text{miles} \cdot \frac{\text{feet}}{\text{miles}} \]

in other words you need the ratio of feet per mile. Can you write down the ratio of feet per mile?

Answer 5

We need to convert 36 miles per hour to feet per sec (ft/sec).
We know two crucial facts: 1hr=3600 sec., and 1 mile = 5280 feet.

1) convert miles to feet:

\[\frac{ 36 miles }{ hour }*\frac{ 5280 feet }{ 1 mile }\]

Answer 6

(2) Convert hours to seconds:
\[\frac{ 36 miles }{ 1 hour }\frac{ 5280 feet }{ 1 mile }\frac{ 1 hour }{ 3600 \sec }.\]

Cancel "hour" and "miles". Multiply as indicated.

Answer 7

1 mile is equal to 5280 feet
you use that to write 1 mile per 5280 feet or
\[ \frac{ \text{1 mile}}{\text{5280 feet}}\]
but that is upside down (we want feet "up top") so "flip it"
\[ \frac{\text{5280 feet}}{ \text{1 mile}}\]

that is the ratio you use to convert miles to feet
\[ 36 \text{ miles} \cdot \frac{\text{5280 feet}}{ \text{1 mile}} \]
will give you the number of feet in 36 miles.