Unit Conversions

Are Units important? 3

$327.6 million total for both orbiter and lander. Are Units important? Project Cost $327.6 million total for both orbiter and lander. $193.1 million for spacecraft development, $91.7 million for launch $42.8 million for mission operations. http://mars.jpl.nasa.gov/msp98/orbiter/ 4

Are Units important? "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." http://mars.jpl.nasa.gov/msp98/orbiter/ 4

Convert 10.0 inches to centimeters Converting Inches to centimeters Convert 10.0 inches to centimeters

Converting Inches to centimeters 10.0 in 1 We start by writing down the number and the unit as a FRACTION

Converting Inches to centimeters 10.0 in 2.54 cm 1 in 1 x Our conversion factor for this is 1 in = 2.54 cm. Since we want to convert to cm, it goes on the top.

Converting Inches to centimeters 10.0 in 2.54 cm 1 in 1 x Now we cancel and collect units. The inches cancel out, leaving us with cm – the unit we are converting to.

Converting Inches to centimeters 10.0 in 2.54 cm 25.4 cm = 1 in 1 The x 1 in 1 Since the unit is correct, all that is left to do is the arithmetic... The Answer

Even though we have two different numbers and two different units, they represent the exact same length. You can check this by looking at a ruler – find the 10 in mark and directly across at the cm side. What number do you find?

A more complex conversion km to m hr s In order to work a NSCI 110 homework problem, we need to convert kilometers per hour into meters per second. We can do both conversions at once using the same method as in the previous conversion.

A more complex conversion km to m hr s Step 1 – Write down the number and the Unit as Fraction! 80 km 1 hr

A more complex conversion km to m hr s 80 km 1 hr x 1 hr 3600 s First we’ll convert time. Our conversion factor is 1 hour = 3600 sec. Since we want hours to cancel out, we put it on the top.

A more complex conversion km to m hr s 80 km 1 hr 1000 m x x 1 hr 3600 s 1 km Next we convert our distance from kilometers to meters. The conversion factor is 1 km = 1000 m. Since we want to get rid of km, this time it goes on the bottom.

A more complex conversion km to m hr s 80 km 1 hr 1000 m m = x x s 1 hr 3600 s 1 km Now comes the important step – cancel and collect units. If you have chosen the correct conversion factors, you should only be left with the units you want to convert to.

A more complex conversion km to m hr s 80 km 1 hr 1000 m = x x 1 hr 3600 s 1 km 80,000 m Since the unit is correct, we can now do the math – simply multiply all the numbers on the top and bottom, then divide the two. 3600 s

A more complex conversion km to m hr s 80 km 1 hr 1000 m = x x 1 hr 3600 s 1 km 80,000 m m 22.2 The Answer!! = s 3600 s

both velocities. A car that is exact same velocity as a car 80 km/hr and 22.2 m/s are both velocities. A car that is moving at a velocity of 80 km/hr is traveling the exact same velocity as a car traveling at 22.2 m/s.

Convert a rate from one unit to another with a change in both units                                                                                                                                                                                                                                                         

Convert a rate from one unit to another with a change in both units