Converting Units Likely the most useful thing you will learn all year.
Lecture Part A. ( Just watch and think ) A sign along the road in Canada says “100 kilometers/hour.” What is this in miles per hour?
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1.61 km = 1 mile & 1 km = miles =
1.61 km = 1 mile & 1 km = miles =
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Lecture Part B. ( Just watch and think ) An airplane has a speed of 600 miles per hour. How fast is this in miles per minute?
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= 1 hour = 60 minutes
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= 10 miles/min is the same speed as 600 miles/hour
= Wait a tick… Why does this method work?
x ÷ x = ?
= ?
= 1
= This method works because when you multiply by 1 you do not change the value of the quantity. 1
1a. The piece of paper on your desk is 8 1 / 2 inches by 11 inches. In centimeters, how wide is the page?
= cm
How many centimeters equals how many inches? = cm
2.54 centimeters = 1 inch = cm
2.54 centimeters = 1 inch
= 21.6 cm The piece of paper is 21.6 cm wide.
1b. What is the width of the page, in feet?
What is the width of the page, in feet? What should we start with: 8.50 inches, or 21.6 cm?
= ft
How many feet equals how many inches? = ft
1 foot = 12 inches = ft
1 foot = 12 inches
= ft
= ft The page is feet long
2a. A football field is 100 yards. How many inches is this?
= inches
= 3600 inches
2b. How many kilometers long is a football field?
= km
= km
2c. Looking for some extra practice? How long is a football field in: Miles Meters Inches Centimeters
2c. Answers: Miles [0.057] Meters [91.44] Inches [3600] Centimeters [9144]
3. A student is 17 years old. How many hours old is the student?
=
= hours
= 148,920 hours
4. A sprinter is running at 10 m/s. How fast is this, in miles per hour?
miles =per hour
miles =per hour
miles =per hour
miles = 22 per hour
5. A hotel room in Paris is 110 Euros. How much is this in US Dollars?
€110
= $
€110 = $
1 Euro = 1.4 Dollars 1 Dollar = 0.72 Euros €110 = $
1 Euro = 1.4 Dollars 1 Dollar = 0.72 Euros €110 = $
1 Euro = 1.4 Dollars 1 Dollar = 0.72 Euros €110 = $ 154
6a. A shoe box is 5 inches x 3 inches x 11 inches = 165 cubic inches. How many cubic centimeters is this?
= cm 3
= 2700 cm 3
6b. Extra practice: Your desktop is about 200 square inches. What is this area in square feet and square centimenters?
Answers. The area of your desktop is: 1.38 ft 2 1,290 cm 2
7. The density of water is exactly 1 g/cm 3. What is the density of water in pounds per cubic foot?
= pounds per cubic foot
= 62 pounds per cubic foot
8. A truck can unload 100 kg of stone in 2 minutes. How fast is this, in pounds per second?
= pounds / second
= 1.8 pounds / second
9. A landscaper can move 2 kg of soil every minute. How many hours will it take to move 300 pounds?
= hours
= 1.1 hours
Estimating ≈
Which is greater: A.The number of pieces of printer paper, stacked from floor to ceiling. B.The number of walking steps from the High School to the Middle School. C.They are about the same.
How could we estimate option A.?
About how far is it from the floor to the ceiling? How tall is a package of paper?
= sheets
= 27,000 sheets
About how far away is the middle school? About how big is one step?
= steps
= 3,520 steps
btw, 27,000 steps ≈ distance from here to Solon, OH
Which is greater: A.The number of pieces of printer paper, stacked from floor to ceiling. B.The number of walking steps from the High School to the Middle School. C.They are about the same.
E1a. Estimate how many hours a McDonald’s worker must work to earn enough to buy a car. Assume that all the money goes toward the car. $
How much is a car? What is the wage of a McDonald’s worker?
= hours
= 1000 hours
E1b. How many years is this?
= years
= 0.48 years
E2. If you drove from here to San Francisco, about how many times would you stop for gas?
How far away is San Francisco? How far can you drive on one tank of gas? How far can you drive on one gallon of gas? How many gallons fit in a tank?
= tanks
= 8 tanks
E3. If you wanted to buy sliced turkey to feed the entire senior class, how much would that cost?
How many students is that? How much does each student need? What is the cost, per pound?
= $
= $ 500
E4a. About how many hours have you spent in school?
How many years have you been in school? How many days in a year? How many hours in a day?
= hours
= 15,000 hours
E4b. About what percentage of your life have you spent in school? %
How many hours old are you?
= 150,000 hours
E4c. What percentage of your waking life have you spent in school?
How many hours are you awake every day?
= hours
= 99,000 hours