Joanne Smithies Our Lady & St. Gerards RCP

Are Units important? 3

"The 'root cause' of the loss of the spacecraft was the failed translation of English units into metric units in a segment of ground-based, navigation-related mission software, as NASA has previously announced," said Arthur Stephenson, chairman of the Mars Climate Orbiter Mission Failure Investigation Board. "The failure review board has identified other significant factors that allowed this error to be born, and then let it linger and propagate to the point where it resulted in a major error in our understanding of the spacecraft's path as it approached Mars." 4

Converting units  Factor label method Regardless of conversion, keeping track of units makes things come out right Must use conversion factors  - The relationship between two units Canceling out units is a way of checking that your calculation is set up right!

 Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer.

Common conversion factors Factor  EnglishFactor  1 gallon = 4 quarts4 qt/gal or 1gal/4 qt  1 mile = 5280 feet5280 ft/mile or 1 mile/5280 ft  1 ton = 2000 pounds 2000 lb/ton or 1 ton/2000 lb  Common English to Metric  1 liter = quarts qt/L or 1 L/1.057 qt or L/qt  1 kilogram = 2.2 pounds 2.2 lb/kg or 1 kg/2.2 lb  or kg/lb  1 meter = yards yd/m or 1m/1.094 yd  or 0.917m/yd  1 inch = 2.54 cm 2.54 cm/inch or 1 in/2.54 cm

Example: Convert the Following (1) 32 ft. = ___ yd.(2) 60 in. = ___ ft.

Example: Convert the Following (1) 72 oz. = ___ C(2) 4 qt. = ___ gal.

Example: Convert the Following (1) 12 lbs. = ___ oz.(2) 192 oz. = ___ lb.

Example: Convert the Following (1) 500 cm. = ___ m(2) 8,000 g = ___ kg.