Christmas Vacation Take Home Test

Plus Q's 1, 6 & 7 2007 Free Response Form A

Due the first Day Back From Break

Name

(Justify Answers!!! Show Work on Test)

An object is thrown with a horizontal velocity of 20 m/s from a cliff that is 125 m above level ground. If air resistance is negligible, the time that it takes the object to fall to the ground from the cliff is most nearly:

a) 3 s

b) 5 s

c) 6 s

d) 12 s

e) 25s

2. Maria throws two stones from the top edge of a building with a speed of 20 m/s. She throws one straight down and the other straight up. The first one hits the street in a time t₁. How much later is it before the second stone hits?

a. 5 s

b. 4 s

c. 3 s

d. not enough information is given to work this problem

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 250 kg crate. What is the acceleration of the crate if the 800 N force is maintained after the crate begins to move and the coefficient of kinetic friction is 0.12?

a. 1.8 m/s²

b. 2.5 m/s²

c. 3.0 m/s²

d. 3.8 m/s²

A 100 kg box is placed on a ramp. As one end of the ramp is raised, the box begins to move downward just as the angle of inclination reaches 15˚. What is the coefficient of static friction between box and ramp?

a. 0.15

b. 0.26

c. 0.77

d. 0.95

A 9 kg hanging weight is connected by a string over a pulley to a 5 kg block sliding on a flat table. If the coefficient of sliding friction is 0.2, find the tension in the string.

a. 18.9 N

b. 24.0 N

c. 32.0 N

d. 37.8 N T

A 7‑kg bowling ball strikes a 2‑kg pin. The pin flies forward with a velocity of 6 m/s, the ball continues forward at 4 m/s. What was the original velocity of the ball?

a. 3.3 m/s

b. 4.0 m/s

c. 5.7 m/s

d. 6.6 m/s

7. In a partially elastic collision between two objects with unequal mass.

a. the velocity of one will increase by the amount that the velocity of the other

decreases.

b. the momentum of one will increase by the amount that the momentum of the other

decreases.

c. the energy of one increases by the amount that the energy of other decreases.

d. the total momentum of the system will decrease.

An ideal monatomic gas is compressed while its temperature is held constant. What happens to the internal energy of the gas during this process and why?

a) It decreases because the gas does work on its surroundings.

b) It decreases because the molecules of an ideal gas collide.

c) It does not change because the internal energy of an ideal gas depends only on its temperature.

d) It increases because work is done on the gas.

e) It increases because the molecules travel a shorter path between collisions.

In the pV diagram (right), the initial state of gas is
shown at point I. Which of the curves represents
a process in which no work is done on or by the gas?

a) I A, I B

b) B F, I A

c) I B F, I A F

d) I B, A F

e) None of the above

An isolated positive charge q is in the plane of the page, as shown to the right. The directions of the electric field vectors at points P and T, which are also in the plane of the page, are given by which of the following?

Point P Point T

a) Left Right

b) Right Left

c) Left Toward the top of the page

d) Right Toward the top of the page

e) Left Toward the bottom of the page

Three resistors connected in parallel have individual values of 4.0, 6.0 and 10.0 W, respectively. If this combination is connected in series with a 12.0 V battery and a 2.0 W resistor, what is the current in the 10 W resistor?

a. 0.59 A

b. 1.0 A

c. 11.2 A

d. 16.0 A

A 10 V emf battery is connected in series with the following: a 2 µF (microfarad) capacitor, a 2 W resistor, an ammeter, and a switch, initially open; a voltmeter is connected in parallel across the capacitor. At the instant the switch is closed, what are the current and capacitor voltage readings, respectively?

a. zero A, 10 V

b. zero A, zero V

c. 5 A, zero V

d. 5 A, 10 V

A 10 V emf battery is connected in series with the following: a 2 mF (microfarad) capacitor, a 2 ohm resistor, an ammeter, and a switch, initially open; a voltmeter is connected in parallel across the capacitor. After the switch has been closed for a relatively long period (several seconds, say). What are the current and capacitor voltage readings, respectively?

a. zero A, 10 V

b. zero A, zero V

c. 5 A, zero V

d. 5 A, 10 V

Two long parallel wires, separated by a distance of d,
carry equal currents I toward the top of the page (same direction).

The magnetic field, due to the wires, at a point halfway between them is:

a) zero in magnitude

b) directed into the page

c) directed out of the page

d) directed to the right

e) directed to the left

S is the source of sound and is moving to the right. A listener L is moving 90% of the speed as source S directly to the right. In which of the following locations will the observer hear the
lowest frequency of sound?

a) A b) B c) C d) D

The wavelength of yellow sodium light in vacuum is 5.89 x 10^-7 m. The speed of this light in glass with an index of refraction of 1.5 is most nearly:

a) 4 x 10^-7 m/s

b) 9 x 10^-7 m/s

c) 2 x 10⁸ m/s

d) 3 x 10⁸ m/s

e) 4 x 10⁸ m/s

Three 4.0 W resistors are connected in parallel to a 12.0 V battery. What is the current in any one of the resistors?

a. 16 A

b. 9.0 A

c. 3.0 A

d. 48 A

A system initially consists of an electron and an incident photon. The electron and the photon collide, and afterward the system consists of the electron and a scattered photon. The electron gains kinetic energy as a result of this collision. Compared with the incident photon, the scattered photon has:

a) the same energy

b) a smaller speed

c) a larger speed

d) a smaller frequency

e) a larger frequency

In an experiment, light of a particular wavelength is incident on a metal surface, and electrons are emitted from the surface as a result. To produce more electrons per unit time but with less kinetic energy per electron, the experimenter should do which of the following?

a) Increase the intensity and decrease the wavelength of the light

b) Increase the intensity and the wavelength of the light

c) Decrease the intensity and the wavelength of the light

d) Decrease the intensity and increase the wavelength of the light

e) None of the above would produce the desired result.

When ¹⁰B is bombarded by neutrons, a neutron can be absorbed and an alpha particle (⁴He) emitted. The kinetic energy of the reaction products is equal to the:

a) kinetic energy of the incident neutron

b) total energy of the incident neutron

c) energy equivalent of the mass decrease in the reaction

d) energy equivalent of the mall decrease in the reaction, minus the kinetic energy of the incident neutron

e) energy equivalent of the mass decrease in the reaction, plus the kinetic energy of the incident neutron.

21. When an object of weight W is suspended from
the center of a massless string as shown above,
the tension at any point in the string is

(A) (B) (C)

(D) (E)

Questions 22‑23

A certain quantity of an ideal gas initially at temperature T_, pressure p₀, and volume V₀ is compressed to one‑half its initial volume. As shown above, the process may be adiabatic (process 1), isothermal (process 2), or isobaric (process 3).

Which of the following is true of the mechanical work done on the gas?

a. It is greatest for process 1.

b. It is greatest for process 3.

c. It is the same for processes I and 2 and less for process 3.

d. It is the same for processes 2 and 3 and less for process 1.

e. It is the same for all three processes.

Which of the following is true of the final temperature of this gas?

a. It is greatest for process 1. b. It is greatest for process 2.

c. It is greatest for process 3. d. It is the same for processes 1 and 2.

e. It is the same for processes 1 and 3.

In a certain process, 400 J of heat is added to a system and the system simultaneously does 100 J of work. The change in internal energy of the system is

a. 500 J b. 400 J c. 300 J d. ‑100 J e. ‑300 J

25. Gas in a chamber passes through the cycle ABCA as shown in the diagram below. In the process AB, 12 joules of heat is added to the gas. In the process BC, no heat is exchanged with the gas. For the complete cycle ABCA, the work done by the gas is 8 joules. How much heat is added to or removed from the gas during process CA ?

(A) 20 J is removed.

(B) 4 J is removed.

(D) 20 J is added.

(E) No heat is added to or removed from the gas.

26. Which of the following is always a characteristic of an adiabatic process?

(A) The temperature does not change (DT = 0).

(B) The pressure does not change (DP = 0).

(D) No heat flows into or out of the system (Q = 0).

(E) No work is done on or by the system (W = 0).

A standing wave of frequency 5 hertz is set up on a string 2 meters long with nodes at both ends and in the center, as shown below.

27. The speed at which waves propagate on the string is

(A) 0.4 m/s

(B) 2.5 m/s

(D) 10 m/s

(E) 20 m/s

28. The fundamental frequency of vibration of the string is

(A) I Hz

(B) 2.5 Hz

(D) 7.5 Hz

(E) 10 Hz

An ideal gas in a closed container initially has volume V, pressure P. and Kelvin temperature T. If the temperature is changed to 3T. Which of the following pairs of pressure and volume values is possible?

(A) 3P and V

(B) P and V

(D) P/3 and V

(E) 3P and 3V

If three identical samples of an ideal gas are taken from initial state I to
final state F along the paths IAF, IF, and IBF as shown in the p V‑diagram
to the right, which of the following must be true?

(A) The work done by the gas is the same for all three paths.

(B) The heat absorbed by the gas is the same for all three paths.

(D) The expansion along path IF is adiabatic.

(E) The expansion along path IF is isothermal.

If the average kinetic energy of the molecules in an ideal gas at a temperature of 300 K is E, the average kinetic energy at a temperature of 600 K is

(A)

(B) E

(C)

(D) 2 E

(E) 4 E

32. The image of the arrow is larger than the arrow itself in which of the following cases?'

(A) I only

(B) II only

(D) II and III only

(E) I, II, and III

Mirror

An object is placed at a distance of 1.5f from a converging lens of focal length f, as shown below. What type of image is formed and what is its size relative to the object?

Type Size

(A) Virtual Larger

(B) Virtual Same size

(D) Real Larger

(E) Real Smaller

A light ray passes through substances 1, 2, and 3, as shown below. The indices of refraction for these three substances are n₁, n₂, and n₃, respectively. Ray segments in 1 and in 3 are parallel. From the directions of the ray, one can conclude that:

(A) n₃ must be the same as n₁

(B) n₂ must be less than n₁

(D) n₁must be equal to 1.00

(E) all three indices must be the same

If the object distance for a converging thin lens is more than twice the focal length of the lens, the image is

(A) virtual and erect

(B) larger than the object

(D) located at a distance between f and 2f from the lens

(E) located at a distance more than by from the lens

An illuminated object is placed 0.30 meter from a lens whose focal length is -0.15. meter. The image is

(A) inverted, real, and 0,30 meter from the lens on the opposite side from the object

(B) upright, virtual, and 0.30 meter from the lens on the opposite side, from the object

(D) upright, virtual, and 0. 10 meter from the lens on the same side as the object

(E) inverted, real, and 0. 10 meter from the lens on the same side as the object

An object is placed as shown in the figure below. The center of curvature C and the focal point F of the reflecting surface are marked. As compared with the object, the image formed by the reflecting surface is

(A) erect and larger

(B) erect and the same size

(D) inverted and larger

(E) inverted and smaller

When one uses a magnifying glass to read fine print, one uses a

(A) converging lens to produce a virtual image of the print

(B) converging lens to produce a real image of the print

(D) diverging lens to produce a real image of the print

(E) diverging lens to produce a virtual image of the print

39. An object swings on the end of a cord as a simple pendulum with period T. Another object oscillates up and down on the end of a vertical spring, also with period T. If the masses of both objects are doubled, what are the new values for the periods?

Pendulum Mass on Spring

(A)

(B) T

(D) T

(E) T

40. An object weighing 4 newtons swings on the end of a string as a simple pendulum. At the bottom of the swing, the tension in the string is 6 newtons. What is the magnitude of the centripetal acceleration of the object at the bottom of the swing?

(A) 0

(B) 1/2g

(D) 3/2 g

(E) 5/2 g

A block of mass m slides on a horizontal frictionless table with an initial speed v. It then compresses a spring of force constant k and is brought to rest. How much is the spring compressed from its natural length?

(A) (B) (C)

(D) (E)

A satellite of mass M moves in a circular orbit of radius R at a constant speed v. Which of the following must be true?

I. The net force on the satellite is equal to and is directed toward the center of the orbit.

II. The net work done on the satellite by gravity in one revolution is zero.

III. The angular momentum of the satellite is a constant.

(A) I only

(B) III only

(D) II and III only

(E) I, II, and III

43. Which three of the glass lenses below, when placed in air, will cause parallel rays of light to converge?

(A) I, II, and III

(B) I, III, and V

(D) II, III, and IV

(E) II, IV, and V

44. An object is placed near a plane mirror, as shown to the right.
Which of the labeled points is the position of the image?

(A) A

(B) B

(D) D

(E) E

An ideal gas is initially in a state that corresponds to point 1 on the graph below, where it has pressure p₁, volume V₁, and temperature T₁. The gas undergoes an isothermal process represented by the curve shown, which takes it to a final state 3 at temperature T₃. If T₂ and T₄ are the temperatures the gas would have at points 2 and 4, respectively, which of the following relationships is true?

(A) T₁ < T₃

(B) T₁ < T₂

(D) T₁ = T₂

(E) T₁ = T₄

The absolute temperature of a sample of monatomic ideal gas is doubled at constant volume. What effect, if any, does this have on the pressure and density of the sample of gas?

Pressure Density

(A) Remains the same Remains the same

(B) Remains the same Doubles

(D) Doubles Is multiplied by a factor of 4

(E) Is multiplied by a Doubles

factor of 4

An ice cube of mass m and specific heat c_i is initially at temperature T₁, where T₁ < 273 K. If L is the latent heat of fusion of water, and the specific heat of water is c_w, how much energy is required to convert the ice cube to water at temperature T₂, where 273 K < T₂ < 373 K?

a. m[c_i (273 ‑ T₁) + L + c_w (373 ‑ T₂)]

b. m[c_i (273 ‑ T₁) + L + c_w (T₂ ‑ 273)]

c. c_i (273 ‑ T₁) + c_w (T₂ ‑ 273)

d. mL + c_w (T₂ ‑ T₁ )

e. mL + (c_w + c_i)( T₂ ‑ T₁)

A concave mirror with a radius of curvature of 1.0 m is used to collect light from a distant star. The distance between the mirror and the image of the star is most nearly

a. 0.25 m b. 0.50 m c. 0.75 m d. 1.0 m e. 2.0 m

An ideal gas undergoes a cyclic process as shown on the graph below of pressure p versus volume V.

49. During which process is no work done on or by the gas?

(A) AB

(B) BC

(C) CD

(D) DE

(E) EA

At which point is the gas at its highest temperature?

(A) A

(B) B

(C) C

(D) D

(E) E

A 10 g piece of aluminum (which has a specific heat of 0.215 cal/gm-C˚) is warmed so that its temperature increases by 5C˚. How much heat was transferred into it?

a. 11 cal

b. 22 cal

c. 34 cal

d. 48 cal

In a greenhouse, electromagnetic energy in the form of visible light enters the glass panes and is absorbed and then reradiated. What happens to this reradiated electromagnetic radiation from within the greenhouse?

a. 100% returns to the atmosphere

b. blocked by glass

c. transformed into ultraviolet upon striking the glass

d. reflected as visible light upon striking the glass

Which of the following best describes a substance in which the temperature remains constant while at the same time it is experiencing an inward heat flow?

a. gas

b. liquid

c. solid

d. substance undergoing a change of state

Mr B. places one end of a steel bar in a Bunsen Burner flame and the other end in an ice cube. By what factor is the rate of heat flow changed when the bar’s cross-sectional area is doubled?

a. 2

b. 1/2

c. 4.0

d. 1/4

Dmitri places one end of a copper rod in a heat reservoir and the other end in a heat sink. By what factor is the rate of heat flow changed when the temperature difference between the reservoir and sink is tripled?

a. 0.33

b. 1/9

c. 3.0

d. 9.0

If one’s hands are being warmed by holding them to one side of a flame, the predominant form of heat transfer is what process?

a. conduction

b. radiation

c. convection

d. vaporization

Which one of the following processes of heat transfer require the presence of a fluid?

a. conduction

b. radiation

c. convection

d. none of the above choices are valid

If cooking is done using an aluminum pan over an electric burner, which of the following will not promote the rate of heat flow from burner to food?

a. increase pan bottom thickness

b. increase pan bottom area

c. increase burner temperature

d. decrease height of pan sides

On a sunny day at the beach, the reason the sand gets so hot and the water stays relatively cool is attributed to the difference in which property between water and sand?

a. mass density

b. specific heat

c. temperature

d. thermal conductivity

Mr B. attaches a falling 500 kg object with a rope through a pulley to a paddle wheel shaft. He places the system in a well‑insulated tank holding 25 kg of water (initially @ 20.0 C˚). When the object falls it causes the paddle wheel to rotate and churn the water. If the object falls a vertical distance of 100 m at constant speed, what is the water’s new temperature? (1 Kcalorie = 4186 J)

a. 15.2 C˚

b. 4825 C˚

c. 24.8 C˚

d. 20.8 C˚

A 0.2 kg aluminum plate, initially at 20˚C, slides down a 15 m long surface, inclined at a 30˚ angle to the horizontal. The force of kinetic friction exactly balances the component of gravity down the plane so that the plate, once started, glides down at constant velocity. If 90% of the mechanical energy of the system is absorbed by the aluminum, what is its temperature increase at the bottom of the incline? (Sp. heat for aluminum is 0.215 kcal/kg-C˚ and 1 kcal = 4186 J.)

a. 0.16 C˚

b. 0.08 C˚

c. 0.04 C˚

d. 0.03 C˚

62. A 0.003 kg lead bullet is traveling at a speed of 240 m/s when it embeds in a wood post. If we assume that half of the resultant heat energy generated remains with the bullet, what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.03 kcal/kg‑C˚, 1 kcal = 4186 J)

a. 115

b. 137

c. 230

d. 259

If heat is flowing from a table to a block of ice moving across the table, which of the following must be true?

a. The table is rough and there is friction between the table and ice.

b. The ice is cooler than the table.

c. The ice is changing phase.

d. All three are possible, but none is absolutely necessary.