New Semester
Started
Get
50% OFF
Study Help!
--h --m --s
Claim Now
Question Answers
Textbooks
Find textbooks, questions and answers
Oops, something went wrong!
Change your search query and then try again
S
Books
FREE
Study Help
Expert Questions
Accounting
General Management
Mathematics
Finance
Organizational Behaviour
Law
Physics
Operating System
Management Leadership
Sociology
Programming
Marketing
Database
Computer Network
Economics
Textbooks Solutions
Accounting
Managerial Accounting
Management Leadership
Cost Accounting
Statistics
Business Law
Corporate Finance
Finance
Economics
Auditing
Tutors
Online Tutors
Find a Tutor
Hire a Tutor
Become a Tutor
AI Tutor
AI Study Planner
NEW
Sell Books
Search
Search
Sign In
Register
study help
sciences
college physics reasoning
College Physics A Strategic Approach 3rd Edition Randall D. Knight, Brian Jones, Stuart Field - Solutions
The two unknown resistors in Figure P23.31 have the same resistance \(R\). When the switch is closed, the current through the battery increases by \(50 \%\). What is \(R\) ? FIGURE P23.31 HilH ww 102 R ww Switch ww
For the circuit of Figure P23.39,a. What is the equivalent capacitance?b. What is the charge of each of the capacitors? 12 V FIGURE P23.39 HHHH 4.0 F 2.0F 1.0 F
After how many time constants has the voltage across a discharging capacitor decayed to \(0.10 \%\) of its initial value?
A capacitor charging circuit consists of a battery, an uncharged \(20 \mu \mathrm{F}\) capacitor, and a \(4.0 \mathrm{k} \Omega\) resistor. At \(t=0 \mathrm{~s}\), the switch is closed; \(0.15 \mathrm{~s}\) later, the current is \(0.46 \mathrm{~mA}\). What is the battery's emf?
A 9.0-nm-thick cell membrane undergoes an action potential that follows the curve in the table on page 748 . What is the strength of the electric field inside the membrane just before the action potential and at the peak of the depolarization? The action potential Depolarization Repolarization
For the real battery shown in Figure P23.55, calculate the power dissipated by a resistor \(R\) connected to the battery when (a) \(R=0.25 \Omega\), (b) \(R=0.50 \Omega\), (c) \(R=1.0 \Omega\), (d) \(R=2.0 \Omega\), and (e) \(R=4.0 \Omega\). (Your results should suggest that maximum power
Batteries are recharged by connecting them to a power supply (i.e., another battery) of greater emf in such a way that the current flows into the positive terminal of the battery being recharged, as was shown in Example 23.1. This reverse current through the battery replenishes its chemicals. The
What is the current through the battery in Figure P23.62 when the switch is (a) open and (b) closed? FIGURE P23.62 10 V 2002 6002 www Switch) 40 1002
What is the ratio \(P_{\text {parallel }} / P_{\text {series }}\) of the total power dissipated by two identical resistors connected in parallel to a battery to the total power when they are connected in series to the same battery?
There is a current of \(0.25 \mathrm{~A}\) in the circuit of Figure P23.65.a. What is the direction of the current? Explain.b. What is the value of the resistance \(R\) ?c. What is the power dissipated by \(R\) ?d. Make a graph of potential versus position, starting from \(V=0 \mathrm{~V}\) in the
A circuit you're building needs an ammeter that goes from \(0 \mathrm{~mA}\) to a full-scale reading of \(50.0 \mathrm{~mA}\). Unfortunately, the only ammeter in the storeroom goes from \(0 \mu \mathrm{A}\) to a fullscale reading of only \(500 \mu \mathrm{A}\). Fortunately, you can make this
A circuit you're building needs a voltmeter that goes from \(0 \mathrm{~V}\) to a full-scale reading of \(5.0 \mathrm{~V}\). Unfortunately, the only meter in the storeroom is an ammeter that goes from \(0 \mu \mathrm{A}\) to a full-scale reading of \(500 \mu \mathrm{A}\). It is possible to use this
The capacitor in an \(R C\) circuit with a time constant of \(15 \mathrm{~ms}\) \(\mathbb{N T}\) is charged to \(10 \mathrm{~V}\). The capacitor begins to discharge at \(t=0 \mathrm{~s}\).a. At what time will the charge on the capacitor be reduced to half its initial value?b. At what time will the
The capacitor in Figure P23.72 is initially uncharged and the switch, in position \(\mathrm{c}\), is not connected to either side of the circuit. The switch is now flipped to position a for \(10 \mathrm{~ms}\), then to position \(\mathrm{b}\) for \(10 \mathrm{~ms}\), and then brought back to
In Example 23.14 we estimated the capacitance of the cell membrane to be \(89 \mathrm{pF}\), and in Example 23.15 we found that approximately \(10,000 \mathrm{Na}^{+}\)ions flow through an ion channel when it opens. Based on this information and what you learned in this chapter about the action
The giant axon of a squid is \(0.5 \mathrm{~mm}\) in diameter, \(10 \mathrm{~cm}\)\(\mathrm{BO}\) long, and not myelinated. Unmyelinated cell membranesINT behave as capacitors with \(1 \mu \mathrm{F}\) of capacitance per square centimeter of membrane area. When the axon is charged to the \(-70
Which pair of graphs in Figure P23.82 best represents the capacitor voltage and the current through the torso as a function of time after the switch is closed?A defibrillator is designed to pass a large current through a patient's torso in order to stop dangerous heart rhythms. Its key part is a
For the values noted in the passage above, what is the time constant for the discharge of the capacitor?A. \(3.2 \mu \mathrm{s}\)B. \(160 \mu \mathrm{s}\)C. \(3.2 \mathrm{~ms}\)D. \(160 \mathrm{~ms}\)A defibrillator is designed to pass a large current through a patient's torso in order to stop
If a patient receives a series of jolts, the resistance of the torso may increase. How does such a change affect the initial current and the time constant of subsequent jolts?A. The initial current and the time constant both increase.B. The initial current decreases, the time constant increases.C.
In some cases, the defibrillator may be charged to a lower voltage. How will this affect the time constant of the discharge?A. The time constant will increase.B. The time constant will not change.C. The time constant will decrease.A defibrillator is designed to pass a large current through a
In an electric eel, each electrocyte can develop a voltage of \(150 \mathrm{mV}\) for a short time. For a total voltage of \(450 \mathrm{~V}\), how many electrocytes must be connected in series?A. 300 B. 450 C. 1500 D. 3000 The voltage produced by a single nerve or muscle cell is quite small, but
An electric eel produces a pulse of current of \(0.80 \mathrm{~A}\) at a voltage of \(500 \mathrm{~V}\). For the short time of the pulse, what is the instantaneous power?A. \(400 \mathrm{~W}\)B. \(500 \mathrm{~W}\)C. \(625 \mathrm{~W}\)D. \(800 \mathrm{~W}\)
Electric eels live in fresh water. The torpedo ray is an electric fish that lives in salt water. The electrocytes in the ray are grouped differently than in the eel; each stack of electrocytes has fewer cells, but there are more stacks in parallel. Which of the following best explains the ray's
The electric catfish is another electric fish that produces a voltage pulse by means of stacks of electrocytes. As the fish grows in length, the magnitude of the voltage pulse the fish produces grows as well. The best explanation for this change is that, as the fish grows,A. The voltage produced by
An elec1ric dipole in a uniform electric field experiences no net force, but it does experience a net torque. The rotation of this dipole will be.A. Clockwise.B. Counterclockwise. E 103 -9 ++q
Does the compass needle rotate?A. Yes, clockwise.B. Yes, counterclockwise.C. No, not at all. Positively charged rod Pivot
A compass is placed next to a bar magnet as shown. Which figure shows the correct alignment of the compass? S A. N S N B. C. D.
The figure shows an edge view of a current loop. Using what you've learned in Figure 24.15, which arrow gives the direction of the field in the center of the loop? D A B
A. compass is placed above a long wire. When a large current is turned on in the direction shown, in which direction will the compass point? I A. B. 7 C. D.
Table 24.1 shows that the strength of the magnetic field 1 cm from a wire carrying a 10 A current is 4 times the earth's field. Referring to Figure 24. 18 for guidance, at what distance from the wire will the field equal that of the earth?A. 2cm B. 4cm C. 8cm D. 16 cm TABLE 24.1 Typical magnetic
An investigator has made a solenoid by wrapping 100 turns of wire on a tube that is 10 cm long and 2 cm in diameter. The power supply is providing as much current as it can, but a stronger field is needed, so the solenoid must be rewrapped. Which of the following will result in a stronger field?A.
These charged particles are traveling in circular orbits with velocities and field directions as noted. Which particles have a negative charge? x X x A. B. C. D.
Four wires carry currents in the directions shown. A uniform magnetic field is directed into the paper as shown. Which wire experiences a force to the left? x X x x X roa X TRO x X X B. C. pyright A. D.
Which way will this current loop rotate?A. Clockwise.B. Counterclockwise.C. The loop will not rotate. B 100
A chain of paper clips is hung from a permanent magnet. Which diagram shows the correct induced pole structure of the paper clips? A. B. S C. S S Z Z N Z SS ZN S S NS NS Z SZ SZ S
In Figure Q24.1, suppose the magnet on the right is fixed in place and the magnet on the left is free to pivot about its center. Will the magnet on the left start to rotate? If so, will it initially rotate clockwise or counterclockwise? FIGURE Q24.1 S N
You have a bar magnet whose poles are not marked. How can you find which pole is north and which is south by using only a piece of string?
If you were standing directly at the earth's north magnetic pole, in what direction would a compass point if it were free to swivel in any direction? Explain.
If you took a sample of magnetotactic bacteria from the northern hemisphere to the southern hemisphere, would you expect them to survive? Explain.
An electron is moving in a circular orbit in a uniform magnetic field. Is the kinetic energy of the electron changing? Explain.
One long solenoid is placed inside another solenoid. Both solenoids have the same length and the same number of turns of wire, but the outer solenoid has twice the diameter of the inner solenoid. Each solenoid carries the same current, but the two currents are in opposite directions, as shown in
Describe the force on the charged particles after they enter the magnetic fields shown in Figure Q24.16. (a) Copyri FIGURE Q24.16 (b) 111
An electron and a proton are moving in circular orbits in the earth's magnetic field, high above the earth's atmosphere. The two particles move at the same speed. Which particle takes more time to complete one orbit? Explain.
A proton moves in a region of uniform magnetic field, as shown in Figure Q24.23. The velocity at one instant is shown. Will the subsequent motion be a clockwise or counterclockwise orbit? FIGURE Q24.23
An unmagnetized metal sphere hangs by a thread. When the north pole of a bar magnet is brought near, the sphere is strongly attracted to the magnet, as shown in Figure Q24.29. Then the magnet is reversed and its south pole is brought near the sphere. How does the sphere respond?A. It is strongly
If If a compass is placed above a current-carrying wire, as in Figure Q24.30, the needle will line up with the field of the wire. Which of the views shows the correct orientation of the needle for the noted current direction? A. B. C. D. FIGURE Q24.30
Four particles of identical charge and mass enter a region of uniform magnetic field and follow the trajectories shown in Figure Q24.33. Which particle has the highest velocity? FIGURE Q24.33 A. B. C. D.
If all of the particles shown in Figure Q24.33 are electrons, what is the direction of the magnetic field that produced the indicated deflection?A. Up.B. Down.C. Out of the plane of the paper.D. Into the plane of the paper. FIGURE Q24.33 A. B. C. D.
Table 24.1 notes that the magnetic field \(10 \mathrm{~cm}\) from a wire carrying a 1 A current is \(2 \mu \mathrm{T}\). What is the field \(1 \mathrm{~cm}\) from the wire? TABLE 24.1 Typical magnetic field strengths Field source and location 10 cm from a wire with 1 A current Field strength (T) 2
Use the data from Table 24.1 to determine at what approximate distance from a wire carrying a current of \(10 \mathrm{~A}\) the magnetic field strength would equal that of a refrigerator magnet. TABLE 24.1 Typical magnetic field strengths Field source and location 10 cm from a wire with 1 A current
For a particular scientific experiment, it is important to be completely isolated from any magnetic field, including the earth's field. The earth's field is approximately \(50 \mu \mathrm{T}\), but at any particular location it may be a bit more or less than this. A 1.00-m-diameter current loop
Two wires carry equal currents in opposite directions, as in Figure P24.5. The field is \(2.0 \mathrm{mT}\) at a point below the lower wire. What are the strength and direction of the field at point 1 and at point 2 , as shown in the figure? FIGURE P24.5 2.0 mT out of page
An investigator places a sample \(1.0 \mathrm{~cm}\) from a wire carrying a large current; the strength of the magnetic field has a particular value at this point. Later, she must move the sample to a \(5.0 \mathrm{~cm}\) distance, but she would like to keep the field the same. By what factor must
Although the evidence is weak, there has been concern in recent years over possible health effects from the magnetic fields generated by transmission lines. A typical high-voltage transmission line is \(20 \mathrm{~m}\) off the ground and carries a current of \(200 \mathrm{~A}\). Estimate the
Two concentric current loops lie in the same plane. The smaller loop has a radius of \(3.0 \mathrm{~cm}\) and a current of \(12 \mathrm{~A}\). The bigger loop has a current of \(20 \mathrm{~A}\). The magnetic field at the center of the loops is found to be zero. What is the radius of the bigger
What is the magnetic field at the center of the loop in Figure P24.17?Figure P24.17 2.0 cm 5.0 A
We have seen that the heart produces a magnetic field that can be used to diagnose problems with the heart. The magnetic field of the heart is a dipole field produced by a loop current in the outer layers of the heart. Suppose that the field at the center of the heart is \(90 \mathrm{pT}\) (a pT is
In the Bohr model of the hydrogen atom, the electron moves in a circular orbit of radius \(5.3 \times 10^{-11} \mathrm{~m}\) with speed \(2.2 \times 10^{6} \mathrm{~m} / \mathrm{s}\). According to this model, what is the magnetic field at the center of a hydrogen atom due to the motion of the
A proton moves with a speed of \(1.0 \times 10^{7} \mathrm{~m} / \mathrm{s}\) in the directions shown in Figure P24.22. A \(0.50 \mathrm{~T}\) magnetic field points in the positive \(x\)-direction. For each, what is the magnetic force on the proton? Give your answers as a magnitude and a direction.
An electron moves with a speed of \(1.0 \times 10^{7} \mathrm{~m} / \mathrm{s}\) in the directions shown in Figure P24.23. A \(0.50 \mathrm{~T}\) magnetic field points in the positive \(x\)-direction. For each, what is the magnetic force on the electron? Give your answers as a magnitude and a
The aurora is caused when electrons and protons, moving in the earth's magnetic field of \(\approx 5.0 \times 10^{-5} \mathrm{~T}\), collide with molecules of the atmosphere and cause them to glow. What is the radius of the circular orbit fora. An electron with speed \(1.0 \times 10^{6} \mathrm{~m}
Problem 24.25 describes two particles that orbit the earth's magnetic field lines. What is the frequency of the circular orbit fora. An electron with speed \(1.0 \times 10^{6} \mathrm{~m} / \mathrm{s}\) ?b. A proton with speed \(5.0 \times 10^{4} \mathrm{~m} / \mathrm{s}\) ?Problem 24.25The aurora
A muon (a charged particle with a mass between that of an electron and a proton that is found in cosmic rays) follows a circular orbit in earth's \(50 \mu \mathrm{T}\) field at a frequency of \(6.8 \mathrm{kHz}\). At what frequency would a muon orbit in Jupiter's more intense \(430 \mu \mathrm{T}\)
Charged particles orbit magnetic field lines in the space above Mars just as they do in the space above earth, but Mars's magnetic field is much weaker so the period of an orbit is much longer. One spacecraft observed a \(1.0 \mathrm{~ms}\) period for electrons orbiting in Mars's magnetic field.
The microwaves in a microwave oven are produced in a special tube called a magnetron. The electrons orbit in a magnetic field at a frequency of \(2.4 \mathrm{GHz}\), and as they do so they emit 2.4 GHz electromagnetic waves. What is the strength of the magnetic field?
A cyclotron is used to produce a beam of high-energy deuterons that then collide with a target to produce radioactive\(\mathbb{N T}\) isotopes for a medical procedure. Deuterons are nuclei of deuterium, an isotope of hydrogen, consisting of one neutron and one proton, with total mass \(3.34 \times
A medical cyclotron used in the production of medical isotopes accelerates protons to \(6.5 \mathrm{MeV}\). The magnetic field in the cyclotron is \(1.2 \mathrm{~T}\).a. What is the diameter of the largest orbit, just before the protons exit the cyclotron?b. A proton exits the cyclotron \(1.0
People have proposed driving motors with the earth's magnetic field. This is possible in principle, but the small field means that unrealistically large currents are needed to produce noticeable torques. Suppose a 20-cm-diameter loop of wire is oriented for maximum torque in the earth's field. What
All ferromagnetic materials have a Curie temperature, a temperature above which they will cease to be magnetic. Explain in some detail why you might expect this to be so.
A solenoid is near a piece of iron, as shown in Figure P24.43. When a current is present in the solenoid, a magnetic field is created. This magnetic field will magnetize the iron, and there will be a net force between the solenoid and the iron.a. Make a sketch showing the direction of the magnetic
A device called a railgun uses the magnetic force on currents to launch projectiles at very high speeds. An idealized model of a railgun is illustrated in Figure P24.48. A \(1.2 \mathrm{~V}\) power supply is connected to two conducting rails. A segment of copper wire, in a region of uniform
Irrigation channels that require regular flow monitoring are often equipped with electromagnetic flowmeters in which the magnetic field is produced by horizontal coils embedded in the bottom of the channel. A particular coil has 100 turns and a diameter of \(6.0 \mathrm{~m}\). When it's time for a
Typical blood velocities in the coronary arteries range from 10 to \(30 \mathrm{~cm} / \mathrm{s}\). An electromagnetic flowmeter applies a magnetic\(\mathbb{N T}\) field of \(0.25 \mathrm{~T}\) to a coronary artery with a blood velocity of \(15 \mathrm{~cm} / \mathrm{s}\). As we saw in Figure
A power line consists of two wires, each carrying a current of \(400 \mathrm{~A}\) in the same direction. The lines are perpendicular to the earth's magnetic field and are separated by a distance of \(5.0 \mathrm{~m}\). Which is larger: the force of the earth's magnetic field on each wire or the
Consider the long rectangular loop in Figure P24.52. If you pass a 1 A current FIGURE P24.52 through the loop, there is a repulsive force between the two long sides of the loop. If the current is increased to \(3 \mathrm{~A}\), by what factor does the magnitude of the force increase? FIGURE P24.52
Bats are capable of navigating using the earth's field-a plus for an animal that may fly great distances from its roost at night. If, while sleeping during the day, bats are exposed to a field of a similar magnitude but different direction than the earth's field, they are more likely to lose their
At the equator, the earth's field is essentially horizontal; near the north pole, it is nearly vertical. In between, the angle varies. As you move farther north, the dip angle, the angle of the earth's field below horizontal, steadily increases. Green turtles seem to use this dip angle to determine
Internal components of cathode-ray-tube televisions and computer monitors can become magnetized; the resulting magnetic field can deflect the electron beam and distort the colors on the screen. Demagnetization can be accomplished with a coil of wire whose current switches direction rapidly and
A 1.0-m-long, 1.0-mm-diameter copper wire carries a current of 50.0 A to the east. Suppose we create a magnetic field that produces an upward force on the wire exactly equal in magnitude to the wire's weight, causing the wire to "levitate." What are the field's direction and magnitude?
A long, straight wire with a linear mass density of \(50 \mathrm{~g} / \mathrm{m}\) is suspended by threads, as shown in Figure P24.58. There is a uniform magnetic field pointing vertically downward. A \(10 \mathrm{~A}\) current in the wire experiences a horizontal magnetic force that deflects it
Assuming the particle in Figure P24.59 is positively charged, what are the directions of the forces due to the electric field and to the magnetic field?A. The force due to the electric field is directed up; the force due to the magnetic field is directed down.B. The force due to the electric field
How does the kinetic energy of the particle in Figure P24.59 change as it traverses the velocity selector?A. The kinetic energy increases.B. The kinetic energy does not change.C. The kinetic energy decreases.In experiments where all the charged particles in a beam are required to have the same
Suppose a particle with twice the velocity of the particle in Figure P24.59 enters the velocity selector. The path of this particle will curveA. Upward.B. Downward.C. Out of the plane of the paper.D. Into the plane of the paper.In experiments where all the charged particles in a beam are required
Next, a particle with the same mass and velocity as the particle in Figure P24.59 enters the velocity selector. This particle has a charge of \(2 q\)-twice the charge of the particle in Figure P24.59. In this case, we can say thatA. The force of the electric field on the particle is greater than
What is the direction of the magnetic force on a singly ionized negative chlorine ion moving in this ocean current?A. EastB. WestC. UpD. DownThe ocean is salty because it contains many dissolved ions. As these charged particles move with the water in strong ocean currents, they feel a force from
What is the magnitude of the force on this ion?A. \(2.8 \times 10^{-23} \mathrm{~N}\)B. \(2.4 \times 10^{-23} \mathrm{~N}\)C. \(1.6 \times 10^{-23} \mathrm{~N}\)D. \(1.4 \times 10^{-23} \mathrm{~N}\)The ocean is salty because it contains many dissolved ions. As these charged particles move with the
What magnitude electric field is necessary to exactly balance this magnetic force?A. \(1.8 \times 10^{-4} \mathrm{~N} / \mathrm{C}\)B. \(1.5 \times 10^{-4} \mathrm{~N} / \mathrm{C}\)C. \(1.0 \times 10^{-4} \mathrm{~N} / \mathrm{C}\)D. \(0.9 \times 10^{-4} \mathrm{~N} / \mathrm{C}\)The ocean is
The electric field produces a potential difference. If you place one electrode \(10 \mathrm{~m}\) below the surface of the water, you will measure the greatest potential difference if you place the second electrode A. At the surface.B. At a depth of \(20 \mathrm{~m}\).C. At the same depth \(10
In the spectrometer shown in Figure P24.67, do the ions have positive or negative charge?A. PositiveB. Negative.If you have a sample of unknown composition, a first step at analysis might be a determination of the masses of the atoms and molecules in the sample. A mass spectrometer to make such an
The moving ions can be thought of as a current loop, and it will produce its own magnetic field. The direction of this field at the center of the particles' circular orbit is A. In the same direction as the spectrometer's magnetic field.B. Opposite the direction of the spectrometer's magnetic
Why is it important that the ions have a known speed?A. The radius of the orbit depends on the mass, the charge, and the speed. If the charge and the speed are the same, the orbit depends on only the mass.B. The orbit must be circular, and this is the case for only a certain range of speeds.C. If
A mass spectrometer similar to the one in Figure P24.67 is designed to analyze biological samples. Molecules in the sample are singly ionized, then they enter a \(0.80 \mathrm{~T}\) uniform magnetic field at a speed of \(2.3 \times 10^{5} \mathrm{~m} / \mathrm{s}\). If a molecule has a mass 85
A microwave oven uses 2.4 GHz electromagnetic waves. A cell phone uses electromagnetic waves at a slightly lower 1.9 GHz frequency. What can you say about the wavelengths of the two?A. The waves from the oven have a longer wavelength.B. The waves from the phone have a longer wavelength.C. The waves
A square conductor moves through a uniform magnetic field directed out of the page. Which of the figures shows the correct charge distribution on the conductor? +++++ +++++ A. B. +++++ 11111 +++++ D. E.
A magnet is below a coil, as shown at right.Referring to Figure 25.13 for guidance, what is the direction of the induced current in the coil if• The magnet is moving toward the coil?• The magnet is held stationary near the coil?• The magnet is moving away from the coil?A. Clockwise.B.
As a coil moves to the right at constant speed, it passes over the north pole of a magnet and then moves beyond it. Which graph best represents the current in the loop for the time of the motion? A counterclockwise current as viewed from above the loop is a positive current, clockwise is a negative
A loop of wire rests in a region of uniform magnetic field. The magnitude o( the field is increasing, thus inducing a current in the loop. Which of the following changes to the situation would make the induced current larger? Choose all that apply.A. Increase the rate at which the field is
Unpolarized light of equal intensity is incident on four pairs of polarizing filters. Rank in order, from largest to smallest, the intensities IA to ID transmitted through the second polarizer of each pair. 30 30% 30 60% 130 60 B. C. D. 30
Two FM radio stations emit radio waves at frequencies of 90.5 MHz and 107.9 MHz. Each station emits the same total power. If you think of the radio waves as photons, which station emits the larger number of photons per second?A. The 90.5 MHz station.B. The 107.9 MHz station.C. Both stations emit
A group of four stars, all the same size, have the four different surface temperatures given below. Which of these stars emits the most red light?A. 3000 K B. 4000 K C. 5000 K D. 6000 K
Showing 1300 - 1400
of 4913
First
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Last
Step by Step Answers