ask a ninja And now for something completely different

The metric system is comprised of 7 : 1. - (unit of length) Is the distance traveled by light in a vacuum during a time interval of 1/ th of a second (unit of mass) equal to the mass of the international prototype kilogram in Sevres, France. metre kilogram base units

3. - (unit of time) based on the decay of a cesium-133 atom unit of electric current 5. - unit of temperature 6. - unit of luminous intensity 7. - unit of amount of substance second Ampere Kelvin candela mole

Prefixes To express larger or smaller amounts of these base units, we use prefixes.

Working with prefixes: Eg) convert 1.4 cm = _______________ m Step 1: Find the prefix on your conversion chart.

3 x 10 8 m/s m km

Significant Digits “The lost and puzzling art of the ancient world”

Okay, so there really isn’t anything strange or puzzling about sig digs (or significant figures, sig figs, are they’re also called by lesser physicists), and I’m certain they weren’t developed in ancient China. Sig digs is a system of rules used to determine how many decimal places answers should be rounded to. The system consists of two easy rules (which will haunt you for the rest of your life!)

Determining the # of Sig Digs All digits in a number are significant. This includes digits before and after the decimal. Scientific notation does not count. Examples: –5  1 sd –4.5  2 sd –89.9  3 sd –3.4 x  2 sd

Zero Rule Zeros to the left of the first digit are only place holders and do not count as sig digs. Zeros to the right of the first digit or inside values count as sig digs. Examples: –0.005  1 sd –1.005  4 sd –  5 sd

Practice: How many sig digs does each of the following values have? –58.00 –5.08 – –1.054 –5.00 x 10 9 –0.001 x 10 5

What are not sig digs? sd do not include: –Exact numbers The mass of 3 goats is 24.5 kg, what is the mass of each goat...the 3 does not count as a sd. –values from the data booklet

Operations with Sig Digs Adding or Subtracting: Your answer should contain the same number of digits after the decimal as the smallest number of digits after the decimal in the question.

Example : = ? _ Answer: But since the 4.5 has only 1 sd after the decimal, then the answer must also only have 1 sd after the decimal – 3.24 = ? _ Answer: 2.16 But we must now change our answer to proper sd… Since the question had, at least, 1 sd after the decimal, the answer must only have 1 sd after the decimal. Proper Answer: 19.3 Example : Proper Answer : 2.2

Multiplying and Dividing Rule: When multiplying or dividing, you must have the same number of sd in your final answer as the least number of sd in your question.

5.8 x 10 2 * = ? _ Answer: Example : Proper Answer : 7.3 x 10 2 Example : Proper Answer : ÷ 1.432= ? _ Answer: …

If you’re lost… Pages 132 of the Textbook.

Do assignment 1

DM

3.3 x 10 2 m/s

Do assignment 2

U2A

1.80 km

46 m

e

Do assignment 3 Do lab 7 uniform motion

N4w

38.5 m

m/s 2

Do assignment 4

Do assignment 5 Do lab Review section 1 quiz

C1Y&list=PL224464F48007F658

Do assignment 6

Do assignment 7

TLYZQ

Do assignment 8 Do lab

EiA&list=FLFh2qGd_dOAiaY5L4tkyeLQ

do assignment 9 Do lab Review section 2 Quiz Unit review Unit exam