Standardized Unit Systems Metric system (SI) – –Système International U.S. customary system (USCS) – –Roots from ancient Middle Eastern civilizations 2-B Unit conversions within systems. Unit conversions between systems.
Conversions within USCS Ex1/103 In the Kentucky Derby, horses race 10 furlongs. How many miles is this? 2-B
Conversions within USCS Ex1/103 In 20,000 Leagues Under the Sea, does the title refer to an ocean depth? 2-B [convert marine leagues to miles]
Conversions within USCS 51’/114 If 150 bushels of wheat are traded on one day, how many cubic inches are traded? how many cubic feet?
International Metric System Invented in France, late 18 th century – –Replace many customary units with a few basic units – –Simplify conversions by using a base 10 system 2-B
International Metric System The basic units are: – –meter (m) for length – –gram (g) for mass – –second (s) for time – –liter (L) for volume 2-B
Metric System - Prefixes 5.23 m 2-B 523 cm.00523 km
Conversions within Metric System Convert 19 decimeters to millimeters: – –conversion or decimal movement: – –1900 millimeters Convert 1378 g to kg: – –conversion or decimal movement: – –1.378 kg 2-B
USCS - Metric Conversions USCS to MetricMetric to USCS 1 in. = 2.540 cm1 cm = 0.3937 in. 1 ft = 0.3048 m 1 m = 3.28 ft 1 yd = 0.9144 m1 m = 1.094 yd 1 mi = 1.6093 km1 km = 0.6214 mi 1 lb = 0.4536 kg1 kg = 2.205 lb 1 fl oz = 29.574 mL1 mL = 0.03381 fl oz 1 qt = 0.9464 L1 L = 1.057 qt 1 gal = 3.785 L1 L = 0.2642 gal 2-B
Conversions between Metric and USCS 60*/114 Convert 1550 millimeters to yards. 63/114 Convert 45 liters to gallons. 65/114 Convert 8550 square feet to square meters. 67/114 Convert 10 kilograms per cubic meter to pounds per cubic foot.
More Practice 103/117 You see oranges in an Italian market priced at 0.8 euro per kilogram. What is the price in dollars per pound? 105/117 A French car manufacturer claims that its newest economy model has gas “mileage” of 20 kilometers per liter. What is the gas mileage in miles per gallon?
Homework 2B – Part I Pages 113-117 #48,50,60,62,68,104,106 2-B
Temperature Units Fahrenheit (US) – –Water freezes at 32ºF, boils at 212ºF Celsius (International) – –Water freezes at 0ºC, boils at 100ºC Kelvin (Scientific) – –Water freezes at 273.15K, boils at 373.15K – –Coldest known temperature = 0 Kelvin (-459.67ºF = -273.15ºC) 2-B
Converting Temperatures (page107) 2-B To Convert fromConversion Formula Celsius to Fahrenheit F = 1.8C + 32 Fahrenheit to CelsiusC = (F-32)/1.8 Celsius to KelvinK = C + 273.15 Kelvin to CelsiusC = K - 273.15
Example Ex6/108 A ‘normal’ human temperature is 98.6ºF What is that in Celsius and Kelvin? 2-B 98.6 o F = 37 o C = 310.15 o K
Energy and Power Energy is what makes matter move or heat up. The international unit of energy is the joule. Power is the rate at which energy is used. The international metric unit of power is the watt, defined as A kilowatt-hour is a unit of energy and 1 kWh = 3600000 joules = 3.6 million joules 2-B 1 kw x 1hr = 1000j/s x 60s/m x 60m/hr x 1 hr
93/116 Your refrigerator uses an average power of 350 watts, and your utility company charges 10 cents per kilowatt- hour of energy. How much does it cost to run your refrigerator for a year? 2-B Conversion: 350 watts is.350 kilowatts (why?) Usage per year in kilowatt-hours:.350 kilowatts x 24 hours/ 1 day x 365 days/1 year = 3066 kilowatt-hours / year Cost per year: 3066 kilowatt-hours / year x.10 $ / 1 kilowatt-hour = 306.60 $ per year
Units of Density/Concentration Density ( e.g. material, population) – describes compactness or crowding. – –material: mass/volume (g/cm 3) – –Population: people/mi 2 Concentration (e.g. pollutants, BAC) describes the amount of one substance mixed with another. – –pollutants: ppm – –BAC: g/100mL (legal limit is 0.08g/100mL) 2-B
Example Ex9/111-2 Manhattan Island has a population of ≈ 1.5 million people living in an area of about 57 km 2. What is its population density? How much space is available per person? 2-B
Example (for fun) Ex9/111-2(cont.) How much space is that per person? Which is roughly 6m×6m, or 20 ft × 20 ft 2-B
Example Ex10/112 An average-sized man has about 5L of blood, and an average 12-ounce beer contains 15g of alcohol. If all the alcohol were immediately absorbed into the bloodstream, what would his BAC be? 2-B
More Practice 79/114 The land area of the US is about 3.5 million square miles, and the population is about 280 million people. What is the average population density? 83/114 A typical glass of wine contains about 20 grams of alcohol. Consider a 110-pound woman, with approximately 4 liters of blood who drinks two glasses of wine. Assuming immediate absorption, what is her BAC?
Homework 2B – Part II Pages 113-117 #70, #72, #80, #84, #94 2-B