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Learn how to convert weight units using both proportion and unit canceling methods with step-by-step explanations and examples in Chapter 7. Discover how to calculate weight in pounds from kilograms and solve word problems efficiently.
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Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in pounds? Step 1. Find a conversion factor that relates the units of interest to one another (page 34 table). 1 kg ≈ 2.205 pounds
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in pounds? Step 2. Express the conversion factor as a ratio (fraction): 1 kg 2.205 pounds
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in pounds? Step 3. Express the problem as a ratio with an unknown: 80 kg ?
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Proportion method) Step 4. Set up a proportion equation such that the units in both numerators are the same and the units in both denominators are the same: 1 kg 2.205 pounds 80 kg ? =
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Proportion method) Step 5. Solve for the unknown: 80 kg (2.205 pounds) ? = 1 kg ? = 176.4 pounds
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Proportion method) Step 6. Check that the answer makes sense ? = 176.4 pounds
Chapter 7: Unit Conversions (Unit canceling method) Convert 2.80 kg to pounds. Step 1. Write the problem as an equation. 2.8 kg = ? pounds
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Unit canceling method) Convert 2.80 kg to pounds. Step 2. Find a conversion factor such that the units cancel (page 34). 1 lb 0.454 kg
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Unit canceling method) Convert 2.80 kg to pounds. Step 3. Place the conversion factor into the equation. 1 lb 0.454 kg 2.80 kg X = ?
Chapter 7: Unit Conversions Chapter 7: Unit Conversions (Unit canceling method) Step 4. Solve the equation; multiply 2.80 kg by the conversion factor: 1 lb 0.454 kg 2.80 kg X ≈ 6.17 lb
Chapter 7: Word Problems Requiring Multiple Steps Transgenic sheep can secrete a human protein, AAT, into their milk. AAT is valuable in the treatment of emphysema. The concentration of AAT in the milk is 15 g/L. A sheep can produce 400 liters of milk each year. AAT is worth $110/gram. What is the value of a year’s production of AAT from such transgenic sheep? 15 g L $110 gram 400 L year = $?/year X X = $660,000/year