chapter 1

Question 1

model

Answer 1

an analogy or representation designed to help us make sense of an unfamiliar phenomenon or experience (ex. the wave model of light)

Question 2

theory

Answer 2

an explanation for patterns in nature that is supported by scientific evidence and has been

Question 3

uncertainty

Answer 3

assumed to be one or two units in the last digit specified (ex. 5.6 cm has an uncertainty of 0.1 cm)

Question 4

percent uncertainty

Answer 4

uncertainty devided by the measured value times 100 (0.1/5.6) x 100 = 1.8%

Question 5

precision

Answer 5

repeatability of the measurement using a given instrument

Question 6

accuracy

Answer 6

refers to how close the measurement is to the true value

Question 7

estimated uncertainty?

Answer 7

takes both accuracy and precision into account

Question 8

significant figures

Answer 8

number of reliably known digits (0.20 has two reliably known digits)

Question 9

scientific notation

Answer 9

a way to determine the number of sig figs (0.00210 x= 2.10 x 10^-3 and has 3 sig figs)

Question 10

when multiplying and dividing numbers:

Answer 10

result should have as many digits as the number with the fewest number of sig figs (2.1 x 3.85 = 8.1)

Question 11

when adding or subtracting:

Answer 11

result is only as precise as the last precise number used (3.6 - 0.57 = 3.0 not 3.03)

Question 12

what is the sum of 1123 m and 10.3 m written with the correct number of sig figs?

Answer 12

1133 meters

Question 13

units

Answer 13

term for the measurement of any quantity (5 kg is 5 portions of a kilogram)

Question 14

How many base units of SI system?

Answer 14

7 base units (table 1.5)

Question 15

derived units

Answer 15

units derived from the 7 base units (newtons, joules, volts)

Question 16

speed SI unit?

Answer 16

meter/second
speed = length/time

Question 17

1 meter is how many feet?

Answer 17

1 meter = 3.2808 feet

Question 18

using conversion factors, determine how many seconds there are in 5.24 days

Answer 18

4.53 x 10^5 seconds

Question 19

Example problem: a typical atom has a diameter of about 1.0 x 10^-10 meters.
a.) What is this in inches?
b.) Approximately how many atoms are along a 1.0 cm line, assuming they touch?

Answer 19

a.) 3.94 x 10^-9 inches
b.) 1.0 x 10^8 atoms

Question 20

Example problem: it is estimated the relative approach speed is 42 m/s.

a.) how many miles per hour does that equal?
b.) could they grab him safely at that speed?

Answer 20

a.) 1m = 3.281 ft 1 mile = 5280 feet. 3600 s = hr
= 94 mph
b.) no

Question 21

What precision should you expect for a quantity that you determine by estimation in which the variables used are rounded to the nearest power of ten?

Answer 21

just the order of magnitude will be correct, the leading number of the digit will not be the same

Question 22

order of magnitude estimate

Answer 22

a rough estimate can be made by rounding off all numbers to one significant figure

• generally work because the estimations of the individual terms

Question 23

how many piano tuners in chicago?

Answer 23

1.) they are approximately 9,000,000 people in Chicago
2.) on average, there are two people per household in Chicago
3.) let’s guess that roughly one household in twenty has a piano that is tuned regularly
4.) they are tuned on average about once per year
5.) (9,000,000 people)/ (2 people per household) * (1 piano/household) * (1 piano tuning per year) = 225,000 piano tuning per year
6.) Piano tuning takes about 2 hours including travel time
7.)The number of tuning that one piano tuner performs is (50 weeks/year)(5 days/week)(8 hours/day)/(2 hours to tune a piano) = 1000 piano tuning a year per piano tuner
8.) (225,000 piano tunings)/(1000 piano tuning per year) = 225 piano tuners

Question 24

equation

Answer 24

a statement of equality, two things are equal

ex. F= ma

Question 25

variable

Answer 25

a symbol which can take on various numerical values ex. Hookes law, F= kx and x is a variable

Question 26

constant

Answer 26

a symbol which has a fixed numerical value, it does not change ex.) Hookes law, F=kx and k is a constant (spring constant)

Question 27

function

Answer 27

a set of paired numbers where each value of an input variable gives one value for the output variable ex.) x(t) = x0 + v0t

Question 28

proportionality

Answer 28

two variables are proportional if there is always a constant ratio between them ex.) F= kx, the ratio F/x always equals k, is k is the proportionality constant

Question 29

dimensional analysis

Answer 29

only quantities with the same dimensions may be added, subtracted, or equated to each other if units are different, apply conversion factor

Question 30

Which of the following is NOT a base unit of the SI system?

Answer 30

volt

Question 31

The metric prefix for one-thousandth is ______

Answer 31

milli

Question 32

The metric prefix for one thousand is ______

Answer 32

kilo

Question 33

What is the sum of 2.67 + 1.976 + 2.1 to the correct precision?

Answer 33

6.7

Question 34

What is the product of 12.56 x 2.12 to the correct number of significant figures?

Answer 34

26.6

Question 35

Which of the following numbers is the smallest? 1) 15 x 10-3 2) 0.15 x 10^0 3) 0.00015 x 10^3 4) 0.00000015 x 10^6

Answer 35

15 x 10-3

Question 36

What is the quantity 13.5 gigameters expressed in decimal notation with standard units?

Answer 36

13,500,000,000 m giga = 10^9

Question 37

Which of the following areas is the largest? 1) 2,500,000 mm2 2) 100,000 cm2 3) 7.5 m2 4) 0.75 m2

Answer 37

100,000 cm2

Question 38

The mass of Mars, 6.40 x 1023 kg, is about one-tenth that of the Earth, and its radius, 3395 km, is about half that of Earth. What is the average density of Mars in kg/m3?

Answer 38

Mass = 6.4 X 10^23 kg Volume = 4/3 pi (r^3) where r = 3.395 X 10^6 m V = 1.639 X 10^20 m^3 So, by merely performing the equation D = M/V you can get the answer easily

Question 39

An average human heart beats at a rate of 70 beats per minute. If someone's heart beats at that average rate over a 70-year lifetime, how many times will it beat?

Answer 39

3 x 10^9

Question 40

The last page of a book is numbered 764. The book is 3.00 cm thick, not counting its covers. What is the average thickness in centimeters of a single sheet of paper in the book?

Answer 40

764 pages, means 764/2 sheets of paper. 3 cm/382 sheets = 8 x 10^-3 cm

Question 41

Which of the following lists contains only SI base units?

Answer 41

candela, kelvin, meter, second

Question 42

Express the number 0.02 volts using one of the prefixes in Table 1-4.

Answer 42

2 centivolts

Question 43

Express the following sum with the correct number of significant figures: 1.00 kg + 1531 g + 2.54 x 10^4 mg.

Answer 43

2.56 kg