physics final
The escape speed for a rocket at Earth's surface is ve. What would be the rocket's escape speed from the surface of a planet with twice Earth's mass and the same radius as Earth?
(2)1/2ve
In the circuit shown above, the capacitor is initially uncharged. The switch S is then closed. A long time after the switch is closed, the current in the 3 Ω resistor is most nearly
.67 A
A charge +Q is inside a hollow region in an electrically neutral piece of solid metal, as shown above. The dashed line represents a Gaussian surface within the metal that completly encloses the hollow region. What is the net electric flux through the Gaussian surface?
0
n the circuit shown above, the capacitor is initially uncharged. The switch S is then closed. Immediately after the switch is closed, the current in the 3 Ω resistor is most nearly
1 A
The diagram above shows equipotential lines produced by an unknown charge distribution. A, B, C, D, and E are points in the plane. How much net work must be done by an external force to move a -1 µC point charge from rest at point C to rest at point E ?
-10x10-6J
A particle moves in simple harmonic motion represented by the graph above. Which of the following represents the velocity of the particle as a function of time?
-4pisinpit
Four identical charged particles, each with charge Q, are fixed in place in the shape of an equilateral pyramid with sides of length L, as shown above. What is the electrical potential energy of this arrangement of charges?
6/4pie0 (q^2/L)
To stretch a certain nonlinear spring by an amount x requires a force F given by F = 40x -6x2, where F is in newtons and x is in meters. What is the change in potential energy when the spring is stretched 2 meters from its equilibrium position?
64 J
A 0.2 x10-6 F capacitor and a 0.1 x10-6F capacitor are connected in parallel to a 6 V battery. The potential difference across the 0.2x10-6F capacitor is most nearly.
6V
A block on a horizontal frictionless plane is attached to a spring, as shown above. The block oscillates along the x axis with simple harmonic motion of amplitude A. Which of the following statements about the block is correct?
At x = A, its displacement is at a maximum.
The diagram above shows equipotential lines produced by an unknown charge distribution. A, B, C, D, and E are points in the plane. At which point does the electric field have the greatest magnitude?
B - E is close together
A charged particle traveling with a velocity v in an electric field E experiences a force F that must be
parallel to E
In the circuit shown, what is the current in the 5 ohm resistor?
10 A
An electric field is produced by the very long, uniformly charged rod. If the strength of the E at a distance r from the axis of the rod, at what distance fro the axis is the field strength E/10?
10 r
When lighted, a 100 watt light bulb operating on a 110 volt household circuit has a resistance closest to
100 ohm
A fixed charge distribution produces the equipotential lines shown in the figure above. Which of the following expressions best represents the magnitude of the electric field at point P?
10V/0.04 m
A 12 volt storage battery, with an internal resistance of 2 ohms, is being charged by a current of 2 amperes as shown in the diagram above. Under these circumstances, a voltmeter connected across the terminals of the battery will read
16 V
The electric potential in the xy-plane in a certain region of space is given by V(x,y) = 6x2y -2y3, where x and y are in meters and V is in volts. What is the magnitude of the y-component of the electric field at the point (-1, 2)?
18 v/m
A student is asked to determine the mass of Jupiter. Knowing which of the following about Jupiter and one of its moons will allow the determination to be made? 1. The time it takes for Jupiter to orbit the Sun 2. The time it takes for the moon to orbit Jupiter 3. The average distance between the moon and Jupiter
2 and 3 only
A uniform electric field exists in which of the following regions? 1. around an infinite line of uniform linear charge density 2. on either side of an infinite thin sheet of uniform charge density 3. between the spherical shells of a charged spherical capacitor
2 only
A particle moves in a circle in such a way that the x ¬and y coordinates of its motion are given in meters as functions of time t in seconds by: x = 5cos(3t) y = 5 sin (3t) What is the period of revolution of the particle?
2(3.14)/3 s
The equation of motion of a simple harmonic oscillator is d2x/dt2 = - 9x, where x is displacement and t is time. The period of oscillation is
2pi/3
A block attached to a spring of negligible mass undergoes simple harmonic motion on a frictionless surface. The potential energy of the system is zero at the equilibrium position and has a maximum value of 50 joules. When the displacement of the block is half the maximum value, its Instantaneous kinetic energy is
37.5 J
Three identical conducting spheres are mounted on insulating handles, as shown above. Spheres 1 and 2 have equal charges of +Q and are separated by a fixed distance. They repel each other with an electrostatic force of magnitude F. Sphere 3, initially uncharged, is first touched to sphere 1, then to sphere 2, and then removed. If the charge distribution on each sphere is assumed to always be spherical, the new magnitude of the electrostatic force between spheres 1 and 2 is
3F/8
Satellite X moves around Earth in a circular orbit of radius R. Satellite Y is also in a circular orbit around Earth, and it completes one orbit for every eight orbits completed by satellite X. What is the orbital radius of satellite Y ?
4R
The mass of Planet X is one tenth that of the Earth, and its diameter is one half that of the Earth. The acceleration due to gravity at the surface of Planet X is most nearly
4m/s/s
An electric field is produced by the very long, uniformly charged rod drawn above. If the strength of the electric field is E1 at a distance r, from the axis of the rod, at what distance from the axis is the field strength E1/4?
4r
A capacitor with circular parallel plates of radius R that are separated by a distance d has a capacitance of C. What would the capacitance be if the plates had radius 2R and were separated by a distance d/2 ?
8C
The radius of the Earth is approximately 6,000 kilometers. The acceleration of an astronaut in a perfectly circular orbit 300 kilometers above the Earth would be most nearly
9 m/s/s
An object weighing 120 N is set on a rigid beam of negligible mass at a distance of 3 m from a pivot, as shown above. A vertical force is to be applied to the other end of the beam a distance of 4 m from the pivot to keep the beam at rest and horizontal. What is the magnitude F of the force required?
90 N
A conducting sphere with a radius of 0.10 meter has 1.0 x 10-9 coulomb of charge deposited on it. The electric field just outside the surface of the sphere is
900 V/m
Two small spheres having charges -Q and +4Q are situated as shown. The electric force on a small test charge will be zero if it is placed at point
A
The diagram above shows the electric field lines due to two charged parallel metal plates. X, Y, and Z are locations where charges may be placed. Which of the following is true?
A positive charge at X would experience the same force if it were placed at Z
Five air-filled parallel plate capacitors have the plate areas and plate separations listed below, where A and d are constants. The capacitors are each connected to the same potential difference. Which capacitor stores the greatest amount of energy?
Area: 2A separation: d/2
the following configurations of electric charges located at the vertices of an equilateral triangle. Point P is equidistant from the charges. In which configuration is the electric field at P pointed at the midpoint between two of the charges?
C
A point charge is placed at the center of an uncharged, spherical, conducting shell of radius R. The electric fields inside and outside the sphere are measured. The point charge is then moved off center a distance R/2 and the fields are measured again. What is the effect of the electric fields?
Changed inside but not changed outside
A conducting spherical shell of radius R has charge q uniformly distributed on its outer surface. The graph above represents electric field strength E versus distance r from the center of the spherical shell. Which of the following graphs best represents E versus r when the charge on the spherical shell is doubled to 2q ?
D
A solid nonconducting sphere of radius R has a charge Q uniformly distributed throughout its volume. A Gaussian surface of radius r with r < R is used to calculate the magnitude of the electric field E at a distance r from the center of the sphere. Which of the following equations results from a correct application of Gauss's law for this situation?
D
A conducting plate and a conducting cylinder are connected to a battery, as shown. Which of the following best represents the electric field between the two objects?
E
A small sphere of mass m and charge +q is constrained to move vertically in an insulating cylinder, as shown above. At the bottom of the cylinder is a point charge +Q. At what height H above the bottom of the cylinder will the small sphere of mass m he in equilibrium?
E
Two identical conducting spheres are charged to +2Q and ‑Q. respectively, and are separated by a distance d (much greater than the radii of the spheres) as shown above. The magnitude of the force of attraction on the left sphere is F1 After the two spheres are made to touch and then are reseparated by distance d the magnitude of the force on the left sphere is F2. Which of the following relationships is correct?
F1 =8 F2
Which of the following describes the electric field and electric potential inside a charged solid spherical conductor that is electrostatic equilibrium?
Field: zero Potential: nonzero nd uniform
Charge +Q is located at the center of the hollow metal sphere shown in cross section above. The net charge on the sphere is zero. What are the induced charges, if any, on the inner and outer surfaces of the sphere?
Inner surface: -Q Outer surface: +Q
A comet moves in the Sun's gravitational field, following the path shown above. What happens to its angular momentum as it moves from point X to point Y ?
It remains constant.
The figure above represents satellites S2 and S3 of equal mass orbiting Earth in circles of radii 2Re, and 3Re respectively, where Re is the radius of Earth. How do the kinetic energy and the angular momentum of S3 compare with those of S2?
Kinetic energy: Less for S3 angular momentum: Greater for S3
A small satellite is in an elliptical orbit around the Earth. The distances RA and RB, are the maximum and minimum distances, respectively, of the satellite from the Earth's center. Let L be the angular momentum and K the kinetic energy of the satellite. A quantity with subscript A or B denotes the instantaneous value of the quantity at the position A or B, respectively. Which of the following must be true?
LB=LA and KB>KA
What is the acceleration of an object of mass 4.5 x 10-5 kg with a charge of 9 x 10-9 C under the influence of an electric field of magnitude 5000 V/m, assuming gravity is negligible?
MA=QE 1 m/s2
A small positively charged sphere is lowered by a nonconducting thread into a grounded metal cup without touching the inside surface of the cup, as shown above. The grounding wire attached to the outside surface is disconnected and the charged sphere is then removed from the cup. Which of the following best describes the subsequent distribution of excess charge on the surface of the cup?
Negative charge resides on the outside surface, and no charge resides on the inside surface.
Two identical massless springs are hung from a horizontal support. A block of mass 1.2 kilograms is suspended from the pair of springs, as shown above. When the block is in equilibrium, each spring is stretched an additional 0.15 meter. When the block is set into oscillation with amplitude A, it passes through its equilibrium point with a speed v. In which of the following cases will the block, when oscillating with amplitude A, also have speed v when it passes through its equilibrium point? I. The block is hung from only one of the two springs. II. The block is hung from the same two springs, but the springs are connected in series rather than in parallel. III. A 0.5 kilogram mass is attached to the block.
None
The electric potential is 50 V at point X and 70 V at point Y. What is the minimum average power needed by an external force to move a charge of 4µC from rest at X to rest at Y in 5 s ?
P=QV/T 1.6x10-3 W
Two concentric, spherical conducting shells have radii r1 and r2 and charges Q1 and Q2, as shown above. Let r be the distance from the center of the spheres and consider the region r1 < r < r2. In this region the electric field is proportional to
Q1/r2
A simple pendulum of length L. whose bob has mass m, oscillates with a period T. If the bob is replaced by one of mass 4m, the period of oscillation is
T
The block shown above is attached to a rigid wall by means of an ideal spring and moves on a horizontal surface with negligible friction. The block oscillates with a period T. If a second ideal spring, identical to the first, is placed above the first spring and attached to the wall and the block, the new oscillation period of the block is
T/(2)^1/2
Which of the following is true for a system consisting of a mass oscillating on the end of an ideal spring?
The maximum kinetic energy and maximum potential energy are equal, but occur at different times.
A block on a horizontal frictionless plane is attached to a spring, as shown above. The block oscillates along the x axis with simple harmonic motion of amplitude A. Which of the following statements about energy is correct?
The potential energy of the spring is at a minimum at x = 0.
Two negative point charges area distance x apart and have potential energy U. If the distance between the point charges increases to 3x, what is their new potential energy?
U/3
Charge +Q is located at the center of the hollow metal sphere shown in cross section above. The net charge on the sphere is zero. If the potential of the inner surface is V, what is the potential of the outer surface?
V
A charge +Q is inside a hollow region in an electrically neutral piece of solid metal, as shown above. The dashed line represents a Gaussian surface within the metal that completly encloses the hollow region. Which of the following correctly relates the electric potentials V at points X, Y , and Z?
VZ<Vy<Vx
Two identical capacitors, X and Y, are connected in series across a battery. A dielectric material with κ = 5 is placed in capacitor X. Once equilibrium is reached, how do the potential differences across the two capacitors and their charges compare?
Vx<Vy Qx=Qy
A charge +Q is inside a hollow region in an electrically neutral piece of solid metal, as shown above. The dashed line represents a Gaussian surface within the metal that completly encloses the hollow region. At which of the three labeled points in the electric field equal to zero?
Y only
If the only force acting on an electron is due to a uniform electric field, the electron moves with constant
acceleration in a direction opposite to that of the field
When a voltage V is connected across a capacitor of capacitance C, charges of equal magnitude Q and opposite sign are on the plates, and the energy stored in the capacitor is U. If C is doubled and V is not changed, how are Q and U affected?
both doubled
Four identical charged particles, each with charge Q, are fixed in place in the shape of an equilateral pyramid with sides of length L, as shown above.One of the four charged particles is released and allowed to move away under the influence of the electrostatic force from the other three charges. How much kinetic energy will it have when it is very far away?
c
The forces produced by two springs as they are stretched are shown in the graph above. Spring 1 indicated by the dashed line is linear but spring 2 is not. The period of oscillation for a mass attached to spring 2 is
dependent on amplitude but never greater than for spring 1
The electric field E just outside the surface of a charged conductor is
directed perpendicular to the surface
An ideal spring with spring constant k is cut in half. What is the spring constant of either one of the two half springs.
k
A thin ring of radius R has charge Q distributed uniformly around the ring. The center of the ring is at the origin of an x-axis perpendicular to the plane of the ring, as shown in the figure above. A point charge +q on the x axis at position x=R is released from rest. What is its kinetic energy when it reaches position P at x=2R on the x-axis?
kQq/r(1/sqrt2 - 1/sqrt5)
Resistors of resistance 4Ω, 2Ω , and 3Ω are connected in a circuit, as shown above. The currents through the resistors are i4, i2, and i3 respectively. Which of these currents is least and which is greatest?
least i4 greatest i3
When a negatively charged rod is brought near, but does not touch, the initially uncharged electroscope shown above, the leaves spring apart (I). When the electroscope is then touched with a finger, the leaves collapse (II). When next the finger and finally the rod are removed, the leaves spring apart a second time (III). The charge on the leaves is
negative in I, positive in III
A rigid insulated rod, with two unequal charges attached to its ends, is placed in a uniform electric field E as shown above. The rod experiences a
net force to the left and a counterclockwise rotation
A parallel plate capacitor is connected to a battery until fully charged. If the battery remains connected while the separation between the plates is increased, which of the following remains constant?
potential difference between the plates
A parallel plate capacitor of capacitance C consists of two plates area A separated by distance d. The upper and lower plates are given a net charge of +q and -q, respectively. What is the electric field between the plates?
q/(Cd)
Two objects of equal mass hang from independent springs of unequal spring constant and oscillate up and down. The spring of greater spring constant must have the
shorter period of oscillation
Two point charges of unknown magnitudes q1 and q2 are placed as shown above. The electric field intensity is zero at point P, which is closer to q1 than to q2. Which of the following is true of the signs of the charges and their magnitudes?
signs: same magnitudes: q1<q2
. A physics problem starts: "A solid sphere has charge distributed uniformly throughout . . ." It may be correctly concluded that the
sphere is not made of metal
A spring which does not obey Hooke's law supplies a force of magnitude ax2, where x is measured downward from the equilibrium position of the unloaded spring and a is a constant. A mass m is attached to the end of the spring and is released from rest at x=0. What is its maximum downward displacement?
sqrt 3mg/a
Two small spheres having charges of +2Q and -Q are located 12 centimeters apart. The potential of points lying on a line joining the charges is best represented as a function of the distance x from the positive charge by which of the following
straight a little under
Two identical stars, a fixed distance D apart, revolve in a circle about their mutual center of mass, as shown above. Each star has mass M and speed v. G is the universal gravitational constant. Which of the following is a correct relationship among these quantities?
v2 = GM/2D
Which of the following capacitors, each of which has plates of area A, would store the most charge on the top plate for a given potential difference V ?
vacuum with space
A positive charge +Q located at the origin produces an electric field E0 at point P (x=+1, y=0). A negative charge -2Q is placed at such a point as to produce a net field of zero at point P. The second charge will be placed on the
x-axis where x<0
Points R and S are each the same distance d from two unequal charges, +Q and +2Q, as shown above. The work required to move a charge Q from point R to point S is
zero
The figures above show parts of two circuits, each containing a battery of emf ε and internal resistance r. The current in each battery is 1 A, but the direction of the current in one battery is opposite to that in the other. If the potential differences across the batteries' terminals are 10 V and 20 V as shown, what are the values of ε and r?
ε =15 V, r= 5 Ω
