Transcript Unit Conversions - HCC Learning Web

MEASUREMENT
Unit Conversions
I
II
III
Are Units important?
On 9/23/99, $125,000,000
Mars Climate Orbiter
entered Mar’s atmosphere
100 km (62 miles) lower
than planned and was
destroyed by heat.
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
1 lb = 1 N
1 lb = 4.45 N
3
Dimensional Analysis
 The “Factor-Label” Method
 Units, or “labels” are canceled, or
“factored” out
g
cm 

g
3
cm
3
Dimensional Analysis
 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.
Dimensional Analysis
 How many milliliters are in 1.00 quart of
milk?
qt
mL
1.00 qt

1L
1000 mL
1.057 qt
1L
= 946 mL
Converting Area and Volume
Caution: Make sure the units cancel
Area: 150 ft2 to yd2
150 ft2 1 yd 1 yd
3 ft 3 ft
150 ft2 (10)2 yd2
OR
(3)2 ft2
Volume: 12 ft3 to Liters
12 ft3
16
(12)3 in3 (2.54)3 cm3 (1)3 m3
1000 L
(1)3 ft3 (1)3 in3
(100)3 cm3 1 m3