Okay,

Radius, is half of the diameter.
Diameter, is the line that splits the circle in half.

1). R=50 D=100
2). R=10 D=20
3). R=5 D=10
4). R=29 D=58
5). R=11 D=22
6). R=31.5 D=63
7). R=45 D=90
8). R=7 D=14
9). R=49 D=98

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4 years ago

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The radius of the tires of a car is 18 inches, and they are revolving at the rate of 651 revolutions per minute. How fast is the

Mumz [18]

So the car is moving at 651 revolutions per minute, with wheels of a radius of 18inches

so, one revolution, is just one go-around a circle, and thus 2π, 651 revolutions is just 2π * 651, or 1302π, the wheels are moving at that "angular velocity"

now, what's the linear velocity, namely, the arc covered per minute

well $\bf v=rw\qquad 
\begin{cases}
v=\textit{linear velocity}\\
r=radius\\
w=\textit{angular velocity}\\
----------\\
r=18in\\
w=1302\frac{\pi }{min}
\end{cases}\implies v=18in\cdot \cfrac{1302\pi }{min}
\\\\\\
v=\cfrac{23436\pi\ in}{min}$

now, how much is that in miles/hrs? well
let's keep in mind that, there are 12inches in 1foot, and 5280ft in 1mile, whilst 60mins in 1hr

thus $\bf \cfrac{23436\pi\ in}{min}\cdot \cfrac{ft}{12in}\cdot \cfrac{mi}{5280ft}\cdot \cfrac{60min}{hr}\implies \cfrac{23436\cdot \pi \cdot 60\ mi}{12\cdot 5280\ hr}$

notice, after all the units cancellations, you're only left with mi/hrs

4 0

3 years ago