Section 9.3 Measures of Weight and Temperature Math in Our World

Learning Objectives  Converting weights in the English system.  Converting weights in the metric system.  Converting weights between English and metric units.  Converting temperatures between the Fahrenheit and Celsius scales.

Units of Weight English Units 16 ounces (oz) = 1 pound (lb) 2,000 lb = 1 ton (T) Metric Units 1 kilogram (kg) = 1,000 grams (g) 1,000 kg = 1 metric ton (t) English/Metric Conversions 1 kg ≈ 2.2 lb 1 oz ≈ 28 g

EXAMPLE 1 Converting Weights in the English System According to the Guinness Book of World Records, the largest healthy baby ever delivered weighed 360 ounces. How much did he weigh in pounds? SOLUTION This is almost exactly 3 times as large as an average newborn boy!

EXAMPLE 2 Converting Weights in the English System An empty Boeing 747 weighs about 175 tons. How much does it weigh in ounces? SOLUTION We will need to first convert tons to pounds, then pounds to ounces.

EXAMPLE 3 Converting Metric Units of Weight Convert each of the following: (a) 150 grams of protein powder to milligrams (b) 23 grams of salt to kilograms

EXAMPLE 3 Converting Metric Units of Weight (a) 150 grams of protein powder to milligrams SOLUTION

EXAMPLE 3 Converting Metric Units of Weight (b) 23 grams of salt to kilograms SOLUTION

EXAMPLE 4 Converting Between English and Metric Units of Weight The heaviest amount ever successfully lifted in Olympic competition was in the clean and jerk competition in Athens in 2004: kg. How many pounds is that?

EXAMPLE 4 Converting Between English and Metric Units of Weight SOLUTION Using dimensional analysis:

EXAMPLE 5 Assessing Weight Loss Megan decides that she absolutely will not go to Florida for spring break unless she loses 15 pounds in the next 3 months. She finds an advertisement online for a British weight loss system that guarantees loss of 3 kg per month. If that claim is true, will she reach her goal?

EXAMPLE 5 Assessing Weight Loss SOLUTION

Conversions for Temperature Fahrenheit-Celsius Conversions To convert Celsius to Fahrenheit: To convert Fahrenheit to Celsius:

EXAMPLE 6 Converting Celsius to Fahrenheit In preparing for vacation, Randy and Catalina check the Internet and find that the average temperature over the next week at their destination is predicted to be 28° Celsius. Should they pack coats or bathing suits? SOLUTION Substitute 28 for C in the first formula: Swimsuits and sunblock it is!

EXAMPLE 7 Converting Fahrenheit to Celsius A frozen pizza needs a 450° Fahrenheit oven to cook. Suppose you bought a cheap oven on eBay, and found that it had been scavenged from Romania, so the temperatures on the dial are Celsius. At what temperature should you set the oven? SOLUTION Substitute F = 450 into the second formula: You should set it close to 230°.

Classwork p : 3-27 odd, odd, odd, odd, 73, 77, 79