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Catalyst. *Get a calculator today! 1. Write 700,050,000 in scientific notation 2. Write 7.808 x 10 -2 in ordinary notation 3. How many meters are there in 65 kilometers? 4. How many milliliters are there in 3 liters?. Today’s Agenda. Dimensional Analysis!. What?
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Catalyst *Get a calculator today! 1. Write 700,050,000 in scientific notation 2. Write 7.808 x 10-2 in ordinary notation 3. How many meters are there in 65 kilometers? 4. How many milliliters are there in 3 liters?
Dimensional Analysis! • What? • Converting from one unit to another • Ex. Feet to inches • Why? • Life– converting from feet to miles, hours to days, etc. • Medicine—converting the amount of medication you need for people who weigh different amounts
Why else? • In July 1983, Air Canada Flight 143 ran completely out of fuel about halfway through its flight. Fuel loading was miscalculated because of a misunderstanding of the recently adopted metric system. For the trip, the pilot calculated a fuel needed in kilograms instead of liters. • On September 23, 1999 NASA lost the $125 million Mars Climate Orbiter spacecraft after a 286-day journey to Mars. Miscalculations due to the use of English units instead of metric units apparently sent the craft slowly off course – it missed Mars by 60 miles in all.
What? • Dimensional analysis is the process used to convert between one system of units to another system of units
How? • A conversion factor is when two things are equal. It is a fact that you need to know when converting from one quantity to another. • For example, 12 roses = 1 dozen • 100 pennies = 1 dollar • 1000 meters = 1 kilometer • Others?
How? 1. Write down what you are given. Think of your conversion factor(s). 2. Draw a great big T 3. Fill in the chart below 4. Multiply everything on the top and divide it by everything on the bottom Conversion Factor (unit you want) Number and unit you were given Conversion Factor (unit you were given)
1st Example • How many eggs are in 3.5 dozen? • Start with? • Conversion factor? • End with? • Set up the T-chart
2nd Example • How many feet are there in 39.7 inches? • Start with? • Conversion factor? • End with? • Set up the T-chart
3rd Example • How many seconds are in one month? • 30 days = 1 month • 1 day = 24 hours • 1 hour = 60 min • 1 min = 60 seconds
Challenge Problem • Convert 3600 g/m to kg/cm • Top and bottom units are different • Both need to be changed
DIMENSIONAL ANALYSIS PRACTICE 1. How many milligrams are there in 60 grams? 2. How many pennies are there in 5 dollars? 3. How many quarters are there in 50 dollars? 4. Convert 300 kilometers to millimeters 5. How many feet are there in 72 inches? 6. Convert 400 centimeters to meters 7. How many dozens of eggs do I have if I have 39 eggs. 8. A snail crawls at a rate of 5 m/min. What is the snail’s rate in km/hr?
Exit Slip • 1. Convert 400 milliliters to liters. (Remember, 1000 mL = 1 L) • 2. How many quarters are in 8.6 dollars? • 3. If there are 4.5 Newtons in 1 pound, how many pounds do I have if I have 49 Newtons?