Physics
Physics
1st Edition
Walker
ISBN: 9780133256925
Table of contents
Textbook solutions

All Solutions

Page 120: Lesson Check

Exercise 10
Step 1
1 of 2
$newcommand{tx}$[1]${text{#1}}$

#### Known

A scalar is fully described with a number.

A vector is fully described with a number (its length) and a direction.

Therefore:

The difference is that vectors have direction.

Note that units of measurement are not essential to define a scalar or a vector.

#### Conclusion

The difference is that vectors have direction.

Result
2 of 2
The difference is that vectors have direction.
Exercise 11
Step 1
1 of 2
$newcommand{tx}$[1]${text{#1}}$

#### Known

The magnitude of a vector refers to its length, while the direction refers to its orientation.

#### Conclusion

The magnitude of a vector refers to its length.

Result
2 of 2
The magnitude of a vector refers to its length.
Exercise 12
Step 1
1 of 3
$newcommand{tx}$[1]${text{#1}}$

#### Known

Defining the magnitude of a vector $vec{r}$ as $r$, we have:

$$
begin{align*}
r=sqrt{r^2_x+r^2_y} (tx{Pythagorean theorem.})
end{align*}
$$

Where $r_x$ is the $x$ component and $r_y$ is the $y$ component of the vector.

#### Conclusion

$$
begin{align*}
boxed{r=sqrt{r^2_x+r^2_y}}
end{align*}
$$

Graphically:

Step 2
2 of 3
Exercise scan
Result
3 of 3
$$
begin{align*}
boxed{r=sqrt{r^2_x+r^2_y}}
end{align*}
$$
Exercise 13
Step 1
1 of 2
$newcommand{tx}$[1]${text{#1}}$

#### Known

A vector is defined by its length and direction.

Therefore:

When we solve a vector, it is because we know its length (magnitude) and direction.

#### Conclusion

To know its length and direction.

Result
2 of 2
To know its length and direction.
Exercise 14
Step 1
1 of 2
$newcommand{tx}$[1]${text{#1}}$

#### Known

For a vector $vec{r}$ with $r_x$ and $r_y$ components we have:

$$
begin{align*}
&r=sqrt{r^2_x+r^2_y} (tx{magnitude}) tx{and}\
&theta=tx{tan}^{-1}left(frac{r_y}{r_x}right) (tx{direction})
end{align*}
$$

#### Calculation

a) Therefore if the components are duplicated, the magnitude increases, this is:

$$
begin{align*}
r’=sqrt{(2 r_x)^2+(2 r_y)^2}=2 sqrt{r^2_x+r^2_y}=2 r
end{align*}
$$

$$
begin{align*}
boxed{r’=2 r}
end{align*}
$$

b) The direction angle is the same:

$$
begin{align*}
theta’=tx{tan}^{-1}left(frac{2 r_y}{2 r_x}right)=tx{tan}^{-1}left(frac{r_y}{r_x}right)=theta
end{align*}
$$

$$
begin{align*}
boxed{theta’=theta}
end{align*}
$$

#### Conclusion

a) The magnitude increases.

b) The direction angle is the same.

Result
2 of 2
a) The magnitude increases.

b) The direction angle is the same.

Exercise 15
Step 1
1 of 3
$newcommand{tx}$[1]${text{#1}}$

#### Known

The Pythagorean theorem:

$$
begin{align}
d=sqrt{x^2+h^2}
end{align}
$$

#### Calculation

Givens: $h=24 tx{m}$, $x=320 tx{m}$

From (1):

$$
begin{align*}
d=sqrt{(320 tx{m})^2+(24 tx{m})^2}=321 tx{m}
end{align*}
$$

#### Conclusion

During the descent the plane covers a distance of $321 tx{m}$ meters.

Graphically:

Step 2
2 of 3
Exercise scan
Result
3 of 3
During the descent the plane covers a distance of $321 text{m}$ meters.
Exercise 16
Step 1
1 of 3
$newcommand{tx}$[1]${text{#1}}$

#### Known

For the components of a vector, $r_x$ and $r_y$ and its magnitude r, the following relationships hold:

$$
begin{align*}
theta=tx{tan}^{-1}left(frac{r_y}{r_x}right) tx{or} theta=tx{sin}^{-1}left(frac{r_y}{r}right) tx{or} theta=tx{cos}^{-1}left(frac{r_x}{r}right)
end{align*}
$$

#### Calculation

Givens: $r=2.4 tx{km}=2.4times10^3 tx{m}$, $r_y=160 tx{m}$

Using:

$$
begin{align*}
theta=tx{sin}^{-1}left(frac{r_y}{r}right)=tx{sin}^{-1}left(frac{160 tx{m}}{2.4times10^3 tx{m}}right)=3.8^circ
end{align*}
$$

#### Conclusion

The angle of the road above the horizontal is $3.8^circ$.

Graphically:

Step 2
2 of 3
Exercise scan
Result
3 of 3
The angle of the road above the horizontal is $3.8^circ$.
Exercise 17
Step 1
1 of 3
$newcommand{tx}$[1]${text{#1}}$

#### Known

For a vector $vec{r}$, the components are given by:

$$
begin{align}
r_x=r tx{cos}(theta)hspace{0.5cm} tx{and}hspace{0.5cm} r_y=r tx{sin}(theta)
end{align}
$$

Where $theta$ is the angle that the vector makes with the positive x-axis.
#### Calculation

Givens: $r=760 tx{m}$, $theta=35^circ$ (north of east)

From (1):

$$
begin{align*}
&r_x=(760 tx{m}) tx{cos}(35^circ)=623 tx{m}\
&r_y=(760 tx{m}) tx{sin}(35^circ)=436 tx{m}
end{align*}
$$

#### Conclusion

$$
begin{align*}
boxed{r_x=623 tx{m}hspace{0.5cm} tx{and} hspace{0.5cm} r_y=436 tx{m}}
end{align*}
$$
.

Graphically:

Step 2
2 of 3
Exercise scan
Result
3 of 3
$$
r_x=623 text{m}hspace{0.5cm} text{and} hspace{0.5cm} r_y=436 text{m}
$$
Exercise 18
Step 1
1 of 3
$newcommand{tx}$[1]${text{#1}}$

#### Known

The direction angle of a vector $vec{r}$ with components $r_x$ and $r_y$, is given by:

$$
begin{align}
theta=tx{tan}^{-1}left(frac{r_y}{r_x}right)
end{align}
$$

#### Calculation

Givens: $r_x=22 tx{m}$, $r_y=4.8 tx{m}$

From (1):

$$
begin{align*}
theta=tx{tan}^{-1}left(frac{4.8 tx{m}}{22 tx{m}}right)=12.3^circ
end{align*}
$$

#### Conclusion

$$
begin{align*}
boxed{theta=12.3^circ}
end{align*}
$$

Graphically:

Step 2
2 of 3
Exercise scan
Result
3 of 3
The direction angle is $12.3^circ$.
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Chapter 1: Introduction to Physics
Section 1.1: Physics and the Scientific Method
Section 1.2: Physics and Society
Section 1.3: Units and Dimensions
Section 1.4: Basic Math for Physics
Page 38: Assessment
Page 41: Standardized Test Prep
Chapter 2: Introduction to Motion
Section 2.1: Describing Motion
Section 2.2: Speed and Velocity
Section 2.3: Position-Time Graphs
Section 2.4: Equation of Motion
Page 66: Assessment
Page 71: Standardized Test Prep
Page 45: Practice Problems
Page 47: Practice Problems
Page 47: Lesson Check
Page 49: Practice Problems
Page 52: Practice Problems
Page 53: Lesson Check
Page 56: Practice Problems
Page 57: Lesson Check
Page 59: Practice Problems
Page 60: Practice Problems
Page 62: Practice Problems
Page 62: Lesson Check
Chapter 3: Acceleration and Acceleration Motion
Section 3.1: Acceleration
Section 3.2: Motion with Constant Acceleration
Section 3.3: Position-Time Graphs for Constant Acceleration
Section 3.4: Free Fall
Page 105: Assessment
Page 111: Standardized Test Prep
Chapter 4: Motion in Two Dimensions
Section 4.1: Vectors in Physics
Section 4.2: Adding and Subtracting Vectors
Section 4.3: Relative Motion
Section 4.4: Projectile Motion
Page 144: Assessment
Page 149: Standardized Test Prep
Chapter 5: Newton’s Laws of Motion
Section 5.1: Newton’s Laws of Motion
Section 5.2: Applying Newton’s Laws
Section 5.3: Friction
Page 180: Assessment
Page 187: Standardized Test Prep
Chapter 6: Work and Energy
Section 6.1: Work
Section 6.2: Work and Energy
Section 6.3: Conservation of Energy
Section 6.4: Power
Page 220: Assessment
Page 227: Standardized Test Prep
Page 191: Practice Problems
Page 193: Practice Problems
Page 196: Lesson Check
Page 196: Practice Problems
Page 199: Practice Problems
Page 201: Practice Problems
Page 203: Practice Problems
Page 204: Practice Problems
Page 205: Practice Problems
Page 206: Lesson Check
Page 209: Practice Problems
Page 211: Lesson Check
Page 213: Practice Problems
Page 214: Practice Problems
Page 215: Practice Problems
Page 216: Lesson Check
Chapter 7: Linear Momentum and Collisions
Section 7.1: Momentum
Section 7.2: Impulse
Section 7.3: Conservation of Momentum
Section 7.4: Collisions
Page 260: Assessment
Page 265: Standardized Test Prep
Chapter 8: Rotational Motion and Equilibrium
Section 8.1: Describing Angular Motion
Section 8.2: Rolling Motion and the Moment of Inertia
Section 8.3: Torque
Section 8.4: Static Equilibrium
Page 300: Assessment
Page 305: Standardized Test Prep
Page 269: Practice Problems
Page 271: Practice Problems
Page 272: Practice Problems
Page 275: Practice Problems
Page 275: Lesson Check
Page 277: Practice Problems
Page 280: Lesson Check
Page 284: Practice Problems
Page 286: Practice Problems
Page 287: Practice Problems
Page 289: Lesson Check
Page 294: Practice Problems
Page 295: Practice Problems
Page 296: Lesson Check
Chapter 9: Gravity and Circular Motion
Section 9.1: Newton’s Law of Universal Gravity
Section 9.2: Applications of Gravity
Section 9.3: Circular Motion
Section 9.4: Planetary Motion and Orbits
Page 336: Assessment
Page 341: Standardized Test Prep
Chapter 10: Temperature and Heat
Section 10.1: Temperature, Energy, and Heat
Section 10.2: Thermal Expansion and Energy Transfer
Section 10.3: Heat Capacity
Section 10.4: Phase Changes and Latent Heat
Page 378: Assessment
Page 383: Standardized Test Prep
Chapter 11: Thermodynamics
Section 11.1: The First Law of Thermodynamics
Section 11.2: Thermal Processes
Section 11.3: The Second and Third Laws of Thermodynamics
Page 410: Assessment
Page 413: Standardized Test Prep
Chapter 12: Gases, Liquids, and Solids
Section 12.1: Gases
Section 12.2: Fluids at Rest
Section 12.3: Fluids in Motion
Section 12.4: Solids
Page 446: Assessment
Page 451: Standardized Test Prep
Chapter 13: Oscillations and Waves
Section 13.1: Oscillations and Periodic Motion
Section 13.2: The Pendulum
Section 13.3: Waves and Wave Properties
Section 13.4: Interacting Waves
Page 486: Assessment
Page 491: Standardized Test Prep
Chapter 14: Sound
Section 14.1: Sound Waves and Beats
Section 14.2: Standing Sound Waves
Section 14.3: The Doppler Effect
Section 14.4: Human Perception of Sound
Page 523: Assessment
Page 527: Standardized Test Prep
Page 495: Practice Problems
Page 496: Practice Problems
Page 500: Practice Problems
Page 501: Lesson Check
Page 503: Practice Problems
Page 504: Practice Problems
Page 506: Practice Problems
Page 506: Lesson Check
Page 510: Practice Problems
Page 511: Practice Problems
Page 512: Lesson Check
Page 514: Practice Problems
Page 516: Practice Problems
Page 517: Practice Problems
Page 519: Lesson Check
Chapter 15: The Properties of Lights
Section 15.1: The Nature of Light
Section 15.2: Color and the Electromagnetic Spectrum
Section 15.3: Polarization and Scattering of Light
Page 557: Assessment
Page 563: Standardized Test Prep
Chapter 16: Reflection and Mirrors
Section 16.1: The Reflection of Light
Section 16.2: Plane Mirrors
Section 16.3: Curved Mirrors
Page 590: Assessment
Page 595: Standardized Test Prep
Chapter 17: Refraction and Lenses
Section 17.1: Refraction
Section 17.2: Applications of Refraction
Section 17.3: Lenses
Section 17.4: Applications of Lenses
Page 629: Assessment
Page 635: Standardized Test Prep
Chapter 18: Interference and Diffraction
Section 18.1: Interference
Section 18.2: Interference in Thin Films
Section 18.3: Diffraction
Section 18.4: Diffraction Gratings
Page 668: Assessment
Page 673: Standardized Test Prep
Chapter 19: Electric Charges and Forces
Section 19.1: Electric Charge
Section 19.2: Electric Force
Section 19.3: Combining Electric Forces
Page 698: Assessment
Page 703: Standardized Test Prep
Chapter 20: Electric Fields and Electric Energy
Section 20.1: The Electric Field
Section 20.2: Electric Potential Energy and Electric Potential
Section 20.3: Capacitance and Energy Storage
Page 738: Assessment
Page 743: Standardized Test Prep
Chapter 21: Electric Current and Electric Circuits
Section 21.1: Electric Current, Resistance, and Semiconductors
Section 21.2: Electric Circuits
Section 21.3: Power and Energy in Electric Circuits
Page 775: Assessment
Page 781: Standardized Test Prep
Chapter 22: Magnetism and Magnetic Fields
Section 22.1: Magnets and Magnetic Fields
Section 22.2: Magnetism and Electric Currents
Section 22.3: The Magnetic Force
Page 810: Assessment
Page 815: Standardized Test Prep
Chapter 23: Electromagnetic Induction
Section 23.1: Electricity from Magnetism
Section 23.2: Electric Generators and Motors
Section 23.3: AC Circuits and Transformers
Page 844: Assessment
Page 849: Standardized Test Prep
Chapter 24: Quantum Physics
Section 24.1: Quantized Energy and Photons
Section 24.2: Wave-Particle Duality
Section 24.3: The Heisenberg Uncertainty Principle
Page 876: Assessment
Page 881: Standardized Test Prep
Chapter 26: Nuclear Physics
Section 26.1: The Nucleus
Section 26.2: Radioactivity
Section 26.3: Applications of Nuclear Physics
Section 26.4: Fundamental Forces and Elementary Particles
Page 944: Assessment
Page 947: Standardized Test Prep