Angular Speed

[lewch45]

I need some help with this word problem:

A car with a wheel of radius 14 inches is moving with a speed of 55 mph. Find the angular speed of the wheel in radians per second.

 

[stapel]

What is "55 miles an hour" in terms of "inches per second"?

What is the circumference of the tire?

How many circumferences (rotations) happen in a second at 55 mph?

How many radians is this?

Eliz.

 

[lewch45]

I'm really having trouble converting this problem. Can someone provide any further information, please?

 

[happy]

What kind of information exactly?

 

[tkhunny]

\(\displaystyle \L \frac{55\,miles}{1\,hour}\,*\,\frac{1\,hour}{60\,min}\,*\,\frac{1\,min}{60\,sec}\,*\,\frac{5280\,ft}{1\,mile}\,*\,\frac{12\,in}{1\,ft}\,=\,\)

It's called "Dimensional Analysis". I have heard it called "Multiplying by One (1) - Lots of Times", or something like that. It is a very important concept to learn and skill to carry around in your head.

 

[lewch45]

I actually got some help on this and I'm ok now. Thanks.