Trig: ang. velocity of wheel diam. 24 in on car going 10 mph

masters

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A car is traveling 10 mi/hr. The wheel diameter is 24 inches. What is the angular velocity in radians per second?
 
\(\displaystyle \L \omega = \frac{v}{r}\)

you'll have to convert 10 mph into to ft/sec

you'll also need the wheel's radius in feet.
 
Trig/Physics

10 mi/hr = 14 2/3 ft/s

Radius in feet = 1 foot

C = 2pi

No. of revolutions per sec= 14 2/3 X pi

Now what?
 
Re: Trig/Physics

masters said:
10 mi/hr = 14 2/3 ft/s

Radius in feet = 1 foot

C = 2pi

No. of revolutions per sec= 14 2/3 X pi

Now what?

use the given formula ... \(\displaystyle \L \omega = \frac{v}{r}\), where
\(\displaystyle \L \omega\) is the angular velocity in radians per second
\(\displaystyle \L v\) is the linear velocity of a point on the edge of the wheel, and
\(\displaystyle \L r\) is the wheel's radius.
 
So, v = 14 2/3 ft/sec
and, r = 1 ft

Then Angular velocity = 14 2/3 rad/sec

Right?
 
Re: Trig: ang. velocity of wheel diam. 24 in on car going 10

Hello, masters!

Here's how I baby-talk my way through these . . .


A car is traveling 10 mi/hr. .The wheel diameter is 24 inches.
What is the angular velocity in radians per second?

Convert 10 miles per hour to inches per second . . .

\(\displaystyle \L\frac{10\,\not{\text{miles}}}{1\,\not{\text{hr}}}\,\times\,\frac{5280\,\not{\text{ft}}}{1\,\not{\text{mile}}}\,\times\,\frac{12\,\text{in}}{1\,\not{\text{ft}}} \,\times\,\frac{1\,\not{\text{hr}}}{3600\,\text{sec}} \;=\;176\,\text{in/sec}\)


The circumference of the wheel is: \(\displaystyle 24\pi\) inches.
. . Hence: \(\displaystyle \,1\,\text{rev} \,=\,24\pi\,\text{in}\)

Since \(\displaystyle \,1\text{ rev} \,=\,2\pi\,\text{radians}\)
. . we have: \(\displaystyle \:24\p\,\tex{in} \,=\,2\pi\,\text{rad}\;\;\Rightarrow\;\;12\,\text{in}\,=\,1\,\text{rad}\)


Finally: \(\displaystyle \L\:\frac{176\,\not{\text{in}}}{1\,\text{sec}}\,\times\,\frac{1\,\text{rad}}{12\,\not{\text{in}}}\;-=\;14\frac{2}{3}\,\text{rad/sec}\)

 
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