Basic Units

1
Basic Units

• Length meters
• Mass kilograms
• Time seconds

2

• Temperature Kelvin
• Amount Chm Mole
• Current Amphere
• Luminous In Candela

3
Metric Prefixes

• gt1 lt1
• Mega (M) Micro (m)
• Kilo (k) Nano(n)
• Milli (m) Pico (p)

4
Metric Prefixes

• gt 0
• (G) 109
• (M) 106
• (k) 103

5
Metric Prefixes

• lt 0
• (m) 10-3
• (m) 10-6
• (n) 10-9
• (p) 10-12

6
Accuracy

• How close you are to the real answer

7
Precision

• How well one can repeat his or her work
• Repeatability

8
Uncertainty

• All measurements have a degree of unreliability
• Usually in the last digit of a measurement

9
Significant Digits

• Meaningful digits in a number

10
Multiplication Uncertainty

• The answer should have the same number of
  significant digits as the multiplier with the
  least number of SD
• Same for division

11
Addition Uncertainty

• When adding, line up decimal place add
• The decimal places in the answer should the
  least
• Same for subtraction

12
Determining Significance

• All non-zero digits
• All zeros between non-zero numbers
• All trailing zeros if there is a decimal place

13
When do you leave Sig Figs alone?

• Numbers obtained by counting or by definition are
  exact numbers.
• of students in the classroom
• 2.54 cm 1 inch

14
PERIOD 4 stopped here
15
Scientific Notation

• M x 10n
• M 1.00 ? M lt 10.00
• n an integer

16
Conversion Factor

• Ratio equal to one
• 12 inches/1 foot
• Multiply one unit by a conversion to obtain
  another unit w/o affecting magnitude

17

• PERIOD 4 LEFT OFF HERE

18
Convert

• 2.50 cm to Mm
• 4.2 ns to ms
• 3.15 kg to mg

19
Determine the length in miles of a light year

• Light year distance light travels in one year
• c 3.0 x 108 m/s
• 1 mile 5280 ft
• 1 inch 2.54 cm

20
Convert4.35 kg/L to mg/mL2.31 mm/ns to cm/Ms
21
Calculate the volume in m3 occupied by 750 kg of
gas with 1.50 g/L1 cm3 1 mL
22
Calculate the mass in kg of a board that has
dimensions of 250 mm x 4.0 x 104 mm x 2.5 m and
had a density of 0.80 g/mL1 ml 1 cm3