Sections
Chapter Review

# Chapter Review

### Concept Items

#### 1.1Physics: Definitions and Applications

1.
Which statement best compares and contrasts the aims and topics of natural philosophy had versus physics?
1. Natural philosophy included all aspects of nature including physics.
2. Natural philosophy included all aspects of nature excluding physics.
3. Natural philosophy and physics are different.
4. Natural philosophy and physics are essentially the same thing.
2.

Which of the following is not an underlying assumption essential to scientific understanding?

1. Characteristics of the physical universe can be perceived and objectively measured by human beings.
2. Explanations of natural phenomena can be established with absolute certainty.
3. Fundamental physical processes dictate how characteristics of the physical universe evolve.
4. The fundamental processes of nature operate the same way everywhere and at all times.
3.

Which of the following questions regarding a strain of genetically modified rice is not one that can be answered by science?

1. How does the yield of the genetically modified rice compare with that of existing rice?
2. Is the genetically modified rice more resistant to infestation than existing rice?
3. How does the nutritional value of the genetically modified rice compare to that of existing rice?
4. Should the genetically modified rice be grown commercially and sold in the marketplace?
4.

What conditions imply that we can use classical physics without considering special relativity or quantum mechanics?

1. matter is moving at speeds of less than roughly 1 percent the speed of light,
2. objects are large enough to be seen with the naked eye, and
3. there is the involvement of a strong gravitational field.
1. matter is moving at speeds greater than roughly 1 percent the speed of light,
2. objects are large enough to be seen with the naked eye, and
3. there is the involvement of a strong gravitational field.
1. matter is moving at speeds of less than roughly 1 percent the speed of light,
2. objects are too small to be seen with the naked eye, and
3. there is the involvement of only a weak gravitational field.
1. matter is moving at speeds of less than roughly 1 percent the speed of light,
2. objects are large enough to be seen with the naked eye, and
3. there is the involvement of a weak gravitational field.
5.
How could physics be useful in weather prediction?
1. Physics helps in predicting how burning fossil fuel releases pollutants.
2. Physics helps in predicting dynamics and movement of weather phenomena.
3. Physics helps in predicting the motion of tectonic plates.
4. Physics helps in predicting how the flowing water affects Earth’s surface.
6.
How do physical therapists use physics while on the job? Explain.
1. Physical therapists do not require knowledge of physics because their job is mainly therapy and not physics.
2. Physical therapists do not require knowledge of physics because their job is more social in nature and unscientific.
3. Physical therapists require knowledge of physics know about muscle contraction and release of energy.
4. Physical therapists require knowledge of physics to know about chemical reactions inside the body and make decisions accordingly.
7.
What is meant when a physical law is said to be universal?
1. The law can explain everything in the universe.
2. The law is applicable to all physical phenomena.
3. The law applies everywhere in the universe.
4. The law is the most basic one and all laws are derived from it.
8.
What subfield of physics could describe small objects traveling at high speeds or experiencing a strong gravitational field?
1. general theory of relativity
2. classical physics
3. quantum relativity
4. special theory of relativity
9.

Why is Einstein’s theory of relativity considered part of modern physics, as opposed to classical physics?

1. Because it was considered less outstanding than the classics of physics, such as classical mechanics.
2. Because it was popular physics enjoyed by average people today, instead of physics studied by the elite.
3. Because the theory deals with very slow-moving objects and weak gravitational fields.
4. Because it was among the new 19th-century discoveries that changed physics.

#### 1.2The Scientific Methods

10.
Describe the difference between an observation and a hypothesis.
1. An observation is seeing what happens; a hypothesis is a testable, educated guess.
2. An observation is a hypothesis that has been confirmed.
3. Hypotheses and observations are independent of each other.
4. Hypotheses are conclusions based on some observations.
11.
Describe how modeling is useful in studying the structure of the atom.
1. Modeling replaces the real system by something similar but easier to examine.
2. Modeling replaces the real system by something more interesting to examine.
3. Modeling replaces the real system by something with more realistic properties.
4. Modeling includes more details than are present in the real system.
12.
How strongly is a hypothesis supported by evidence compared to a theory?
1. A theory is supported by little evidence, if any, at first, while a hypothesis is supported by a large amount of available evidence.
2. A hypothesis is supported by little evidence, if any, at first. A theory is supported by a large amount of available evidence.
3. A hypothesis is supported by little evidence, if any, at first. A theory does not need any experiments in support.
4. A theory is supported by little evidence, if any, at first. A hypothesis does not need any experiments in support.

#### 1.3The Language of Physics: Physical Quantities and Units

13.
Which of the following does not contribute to the uncertainty?
1. the limitations of the measuring device
2. the skill of the person making the measurement
3. the regularities in the object being measured
4. other factors that affect the outcome (depending on the situation)
14.
How does the independent variable in a graph differ from the dependent variable?
1. The dependent variable varies linearly with the independent variable.
2. The dependent variable depends on the scale of the axis chosen while independent variable does not.
3. The independent variable is directly manipulated or controlled by the person doing the experiment, while the dependent variable is the one that changes as a result.
4. The dependent and independent variables are fixed by a convention and hence they are the same.
15.

What could you conclude about these two lines?

1. Line A has a slope of $−4.7$
2. Line B has a slope of $12.0$
1. Line A is a decreasing line while line B is an increasing line, with line A being much steeper than line B.
2. Line A is a decreasing line while line B is an increasing line, with line B being much steeper than line A.
3. Line B is a decreasing line while line A is an increasing line, with line A being much steeper than line B.
4. Line B is a decreasing line while line A is an increasing line, with line B being much steeper than line A.
16.

Velocity, or speed, is measured using the following formula: where v is velocity, d is the distance travelled, and t is the time the object took to travel the distance. If the velocity-time data are plotted on a graph, which variable will be on which axis? Why?

1. Time would be on the x-axis and velocity on the y-axis, because time is an independent variable and velocity is a dependent variable.
2. Velocity would be on the x-axis and time on the y-axis, because time is the independent variable and velocity is the dependent variable.
3. Time would be on the x-axis and velocity on the y-axis, because time is a dependent variable and velocity is a independent variable.
4. Velocity would be on x-axis and time on the y-axis, because time is a dependent variable and velocity is a independent variable.
17.
A good-quality measuring tape can be off by $0.50cm$ over a distance of $20m$. What is its percent uncertainty in scientific notation?
1. $2.5×10−2%$
2. $2.5×100%$
3. $2.5×101%$
4. $2.5×102%$
18.
What is the definition of uncertainty?
1. Uncertainty is the number of assumptions made prior to the measurement of a physical quantity.
2. Uncertainty is a measure of error in a measurement due to the use of a non-calibrated instrument.
3. Uncertainty is a measure of deviation of the measured value from the standard value.
4. Uncertainty is a measure of error in measurement due to external factors like air friction and temperature.

### Critical Thinking Items

#### 1.1Physics: Definitions and Applications

19.
In what sense does Einstein’s theory of relativity illustrate that physics describes fundamental aspects of our universe?
1. It describes how speed affects different observers’ measurements of time and space.
2. It describes how different parts of the universe are far apart and do not affect each other.
3. It describes how people think of other people’s views from their own frame of reference.
4. It describes how a frame of reference is necessary to describe position or motion.
20.
Can classical physics be used to accurately describe a satellite moving at a speed of $7500m/s$? Explain why or why not.
1. No, because the satellite is moving at a speed much slower than the speed of the light and is not in a strong gravitational field.
2. No, because the satellite is moving at a speed much slower than the speed of the light and is in a strong gravitational field.
3. Yes, because the satellite is moving at a speed much slower than the speed of the light and it is not in a strong gravitational field.
4. Yes, because the satellite is moving at a speed much slower than the speed of the light and is in a strong gravitational field.
21.
What would be some ways in which physics was involved in building the features of the room you are in right now?
1. Physics is involved in structural strength, dimensions, etc., of the room.
2. Physics is involved in the air composition inside the room.
3. Physics is involved in the desk arrangement inside the room.
4. Physics is involved in the behavior of living beings inside the room.
22.
What theory of modern physics describes the interrelationships between space, time, speed, and gravity?
1. atomic theory
2. nuclear physics
3. quantum mechanics
4. general relativity
23.
According to Einstein’s theory of relativity, how could you effectively travel many years into Earth’s future, but not age very much yourself?
1. by traveling at a speed equal to the speed of light
2. by traveling at a speed faster than the speed of light
3. by traveling at a speed much slower than the speed of light
4. by traveling at a speed slightly slower than the speed of light

#### 1.2The Scientific Methods

24.
You notice that the water level flowing in a stream near your house increases when it rains and the water turns brown. Which of these are the best hypothesis to explain why the water turns brown. Assume you have all of the means to test the contents of the stream water.
1. The water in the stream turns brown because molecular forces between water molecules are stronger than mud molecules
2. The water in the stream turns brown because of the breakage of a weak chemical bond with the hydrogen atom in the water molecule.
3. The water in the stream turns brown because it picks up dirt from the bank as the water level increases when it rains.
4. The water in the stream turns brown because the density of the water increases with increase in water level.
25.

Light travels as waves at an approximate speed of 300,000,000 m/s (186,000 mi/s). Designers of devices that use mirrors and lenses model the traveling light by straight lines, or light rays. Describe why it would be useful to model the light as rays of light instead of describing them accurately as electromagnetic waves.

1. A model can be constructed in such a way that the speed of light decreases.
2. Studying a model makes it easier to analyze the path that the light follows.
3. Studying a model will help us to visualize why light travels at such great speed.
4. Modeling cannot be used to study traveling light as our eyes cannot track the motion of light.
26.

A friend says that he doesn’t trust scientific explanations because they are just theories, which are basically educated guesses. What could you say to convince him that scientific theories are different from the everyday use of the word theory?

1. A theory is a scientific explanation that has been repeatedly tested and supported by many experiments.
2. A theory is a hypothesis that has been tested and supported by some experiments.
3. A theory is a set of educated guesses, but at least one of the guesses remain true in each experiment.
4. A theory is a set of scientific explanations that has at least one experiment in support of it.
27.
Give an example of a hypothesis that cannot be tested experimentally.
1. The structure of any part of the broccoli is similar to the whole structure of the broccoli.
2. Ghosts are the souls of people who have died.
3. The average speed of air molecules increases with temperature.
4. A vegetarian is less likely to be affected by night blindness.
28.
Would it be possible to scientifically prove that a supreme being exists or not? Briefly explain your answer.
1. It can be proved scientifically because it is a testable hypothesis.
2. It cannot be proved scientifically because it is not a testable hypothesis.
3. It can be proved scientifically because it is not a testable hypothesis.
4. It cannot be proved scientifically because it is a testable hypothesis.

#### 1.3The Language of Physics: Physical Quantities and Units

29.

A marathon runner completes a $42.188km$ course in $2h$, $30min$, and $12s$. There is an uncertainty of $25m$ in the distance traveled and an uncertainty of $1s$ in the elapsed time.

1. Calculate the percent uncertainty in the distance.
2. Calculate the uncertainty in the elapsed time.
3. What is the average speed in meters per second?
4. What is the uncertainty in the average speed?
1. $0.059%$, $0.01%$, $0.468m/s$, $0.0003m/s$
2. $0.059%$, $0.01%$, $0.468m/s$, $0.07m/s$
3. $0.59%$, $8.33%$, $4.681m/s$, $0.003m/s$
4. $0.059%$, $0.01%$, $4.681m/s$, $0.003m/s$
30.
A car engine moves a piston with a circular cross section of $7.500±0.002cm$ diameter a distance of $3.250±0.001cm$ to compress the gas in the cylinder. By what amount did the gas decrease in volume in cubic centimeters? Find the uncertainty in this volume.
1. $143.6±0.002cm3$
2. $143.6±0.003cm3$
3. $143.6±0.005cm3$
4. $143.6±0.1cm3$
31.

What would be the slope for a line passing through the two points below?

Point 1: (1, 0.1) Point 2: (7, 26.8)

1. $2.4$
2. $4.5$
3. $6.2$
4. $6.8$
32.
The sides of a small rectangular box are measured $1.80cm$ and $2.05cm$ long and $3.1cm$ high. Calculate its volume and uncertainty in cubic centimeters. Assume the measuring device is accurate to $±0.05cm$.
1. $11.4±0.1cm3$
2. $11.4±0.6cm3$
3. $11.4±0.8cm3$
4. $11.4±0.10cm3$
33.

Calculate the approximate number of atoms in a bacterium. Assume that the average mass of an atom in the bacterium is ten times the mass of a hydrogen atom. (Hint—The mass of a hydrogen atom is on the order of 10−27 kg and the mass of a bacterium is on the order of 10−15 kg .)

1. 1010 atoms
2. 1011 atoms
3. 1012 atoms
4. 1013 atoms

### Problems

#### 1.3The Language of Physics: Physical Quantities and Units

34.

A commemorative coin that sells for $40 is advertised to be plated with 15 mg of gold. Suppose gold is worth about$1,300 per ounce. Which of the following best represents the value of the gold in the coin?

1. $0.33 2.$0.69
3. $3.30 4.$6.90
35.
If a marathon runner runs $9.5miles$ in one direction, $8.89miles$ in another direction and $2.333miles$ in a third direction, how much distance did the runner run? Be sure to report your answer using the proper number of significant figures.
1. $20$
2. $20.7$
3. $20.72$
4. $20.732$
36.
The speed limit on some interstate highways is roughly $80km/h$. What is this in meters per second? How many miles per hour is this?
1. $62m/s$, $27.8mi/h$
2. $22.2m/s$, $49.7mi/h$
3. $62m/s$, $2.78mi/h$
4. $2.78m/s$, $62mi/h$
37.
The length and width of a rectangular room are measured to be $3.955±0.005m$ by $3.050±0.005m$. Calculate the area of the room and its uncertainty in square meters.
1. $12.06±0.29m2$
2. $12.06±0.01m2$
3. $12.06±0.25m2$
4. $12.06±0.04m2$