McGraw Hill Glencoe Algebra 1, 2012
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McGraw Hill Glencoe Algebra 1, 2012 View details
7. Mixed Expressions and Complex Fractions
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Exercise 34 Page 724

a We are given that the speed of an object spinning in a circle equals the circumference of the circle divided by the time it takes the object to complete one revolution. Let's write the defined speed of a spinning object.
We want to write above formula using the variables and (the radius of the circle). To do so, let's first remember the formula for the circumference of the circle.
Now we can substitute   and into the speed formula.
b We are given that a scooter has tires with a radius of inches and the tires make one revolution every seconds. To find the scooter's speed, we will substitute and into the formula that we found in Part A.
Solve for
We found that the speed of the scooter is about inches per second. However, we are asked to find the speed in miles per hour. To do so we will first convert our speed in inches to miles using a conversion factor.
Multiplying inches by this factor will convert it to miles.
Next, we will convert this value in miles per second to miles per hour. To do so we will use the second conversion factor.
To get an accurate value, we will multiply miles per second by the second conversion factor. Let's do it!
Finally, we found that the scooter's speed is about miles per hour.