Physics: Principles and Problems
Physics: Principles and Problems
9th Edition
Elliott, Haase, Harper, Herzog, Margaret Zorn, Nelson, Schuler, Zitzewitz
ISBN: 9780078458132
Textbook solutions

All Solutions

Page 29: Standardized Test Practice

Exercise 1
Step 1
1 of 2
Precision is measured based off of how small of a definite measure a person can measure. The smaller the discrepancy, the more precise a measurement is. The smaller the amount that is $pm$ the more precise the measurement.
Result
2 of 2
C
Exercise 2
Solution 1
Solution 2
Step 1
1 of 6
$$
dfrac{1m}{100cm}; dfrac{1,000m}{1km}
$$
State needed conversions
Step 2
2 of 6
$$
86.2cm cdotdfrac{1m}{100cm}
$$
Multiple to cancel units.
Step 3
3 of 6
.862m
Not A
Step 4
4 of 6
$$
.862m cdot dfrac{1km}{1,000m}
$$
Invert fractions to cancel units
Step 5
5 of 6
$$
8.62 times 10^{-4} km
$$
Result
6 of 6
C
Step 1
1 of 2
To determine which of the following is equal to 86.2 cm, we can do a conversion for each choice as follows:

a). $8.62 text{ m} times frac{100 text{ cm}}{1 text{ m}} = 862 text{ cm}$

b). $0.862 text{ mm} times frac{1 text{ cm}}{10 text{ mm}} = 0.0862 text{ cm}$

c). $8.62 times 10^{-4}text{ km} times frac{1000 text{ m}}{1 text{ km}} times frac{100 text{ cm}}{1 text{ m}} = 86.2 text{ cm}$

d). $862 text{ dm} times frac{10 text{ cm}}{1 text{ dm}} = 8620 text{ cm}$

Based on what he have solved, choice $boxed{C}$ is equal to 86.2 cm.

Result
2 of 2
C
Exercise 3
Solution 1
Solution 2
Result
1 of 1
C. Divide the km by m/s, then divide by 1000.
Step 1
1 of 2
To solve for the time, we can divide the distance by the velocity. This will give a unit of:

$$t = frac{d}{v} = frac{left[text{ km}right]}{[text{m/s}]} = frac{left[text{km s}right]}{left[text{m}right]}$$

Note that in order for the meter unit to cancel, we must multiply the numerator by 1000 to convert the kilometers to meter. Hence, the proper way to solve the time in seconds is to: divide the km by the m/s, then multiply by 1000, which is letter $boxed{B}$.

Result
2 of 2
B
Exercise 4
Step 1
1 of 5
Mark x-axis and y-axis on the graph given in question. This is done so that it becomes easier to map the values in the formula which will be used for determining slope.
Step 2
2 of 5
$slope=dfrac{y_{2}-y_{1}}{x_{2}-x_{1}}$
where $(x_{2},y_{2})$ and $(x_{1},y_{1})$ are points on lying on the line.
Since the graph is a straight line, we can apply the formula for finding slope of a straight line (as written) by identifying 2 points on the line.
Step 3
3 of 5
Mark 2 points on the straight line and name them $(x_{1},y_{1})$ and $(x_{2},y_{2})$. The points are chosen such that the x-axis and y-axis numbers for both the points turns out to be integers. This will help us in solving when we replace these values in the formula for obtaining slope.
Step 4
4 of 5
$(x_{1},y_{1}) = (0 m/s, 0 s)$

$(x_{2},y_{2}) = (8 m/s, 2 s)$

$slope=dfrac{(2-0)m/s}{(8-0)s}=dfrac{1}{4} m/s^{2}=0.25$ $m/s^{2}$

Replace the values for $(x_{1}, y_{1})$ and $(x_{2}, y_{2})$ in the slope formula alongwith the necessary units for quatities represented by $x$ and $y$ axis. Solve and since all our options are in decimals it is better to convert the answer from fraction to decimal with proper units.
Result
5 of 5
A
Exercise 5
Step 1
1 of 5
$$
D = dfrac{m}{V}
$$
original formula. Cross multiply to bring the V to the other side
Step 2
2 of 5
VD = m
Step 3
3 of 5
$$
dfrac{VD}{D} =dfrac{m}{D}
$$
divide by D on both sides
Step 4
4 of 5
$$
V = dfrac{m}{D}
$$
Result
5 of 5
A
Exercise 6
Step 1
1 of 4
a) The equation F=ma rewritten so a is in terms of F and m is: a=$dfrac{F}{m}$
You get this by dividing the left side and right side of the equation by m to isolate the a.
The m/m on the right side cancels out and you are left with

a = F/m

Step 2
2 of 4
b) You will need a conversion factor of $10^{-3}$
There are 1000 grams in 1 kilogram so you need to multiply the grams by $10^{-3}$ with equals 0.001 to get the number of grams in kilograms
Step 3
3 of 4
c) The equation you will use is: a = $dfrac{F}{m}$

The conversion factor is $10^{-3}$, multiply the grams by the conversion factor to get the kilograms:

$350times$ $10^{-3}$ = 0.35 kg

Sub the given F and the m in kg and solve of a:

a = $dfrac{2.7}{0.35}$

= $7.71 m/s^{2}$

$therefore$ the acceleration is $7.7 m/s^{2}$

Result
4 of 4
a) a = $dfrac{F}{m}$
b) $10^{-3}$
c) $7.7 m/s^{2}$
Exercise 7
Step 1
1 of 3
$$
textbf{underline{textit{Solution}}}
$$
Step 2
2 of 3
By plotting the points using Excel, we find that the equation of best fit line ”trend line” is given by the following equation

$$
tag{1} y= -1.03 x + 11.54
$$

$textbf{Or }$we can just draw the line by hands which best fits all the points, and then find the slope from any 2 points on the best fit line with coordinates ($x_1,y_1$) and ($x_2,y_2$) through the following equation

$$
m = dfrac{y_2 – y_1}{x_2 – x_1}
$$

And then we find the point $c$ of $y$-intercept “that is it, the point where $x=0$”, and then substituting in the general equation of the straight line, where

$$
y=mx+c
$$

$textbf{underline{textit{note:}}}$ sometimes we get a physical situation, where the plot best fit line must pass through the origin, intercept at some value in $y$-axis in this problem we are free to chose the $y$-intercept which enables us to have the fitting curve which fits all the points with the least error.

Check, the following $textbf{Graph}$ where we plotted the points in the graph and draw the best fit line whose equation is given by (1)

Exercise scan

Result
3 of 3
$$
y= -1.03 x + 11.54
$$
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