8/27/09

Post date: Aug 26, 2009 6:41:35 PM

• • Operations with significant digits

    • Addition or subtraction

      • Round to the same decimal as the least precise measurement

      • e.g. 1.2 + 3.41 + 12.02 = ?

        • 1.2 is rounded to the tenths place, so answer must be rounded to tenths place

        • 1.2+3.41+12.02=16.63, but rounded to the tenths is 16.6

    • Multiplication or Division

      • Answer has same number of sig digs as the measurement with the fewest sig digs

      • e.g. 3.0 x 14.125

        • 3.0 has 2 sig digs, 14.125 has 5 sig digs, so answer must have 2 sig digs

        • 3.0 x 14.125 = 42.375

        • round to 2 sig digs, so answer is 42

  • Do page 25: 14-17

  • Factor Label Method (more complex)

    • As before, multiply given by 1 in a carefully chosen form

    • Continue this through as many steps as it takes to reach the desired units

    • See page 10 of your lab book for details

  • Convert the following measurements using the factor-label method

    • 4.13 millennia --> minutes

    • 13 ft --> meters

    • 25 miles --> kilometers

    • 15 in --> meters

    • 35 miles per hour --> m/sec

    • 60 kilometers per hour --> miles per hour

    • 300,000,000 meters per second --> miles per hour (this is the speed of light)