Study Guide

Field 114: Physics 
Sample Selected-Response Questions

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General Test Directions

This test contains two sections: (1) a section with selected-response questions and (2) a constructed-response section. The directions for the constructed-response assignment appear before that section.

Each question in the first section is a selected-response question with four answer choices. Read each question and answer choice carefully and choose the  start uppercase ONE end uppercase  best answer. Try to answer all questions. In general, if you have some knowledge about a question, it is better to try to answer it. You will  start uppercase NOT end uppercase  be penalized for guessing.

A calculator is available to you for this test. To access the calculator, click on the calculator icon located in the upper left corner of the screen. A pop-up window containing the calculator will appear. You can reposition the calculator by placing your cursor in the blue area above the calculator and dragging the window to the location of your choice.

Use the numbers on the keyboard and/or point and click with the mouse to enter your computations into the on-screen calculator. When you are finished, close the calculator by clicking the close calculator icon button in the upper right corner of the calculator.

Reference materials will also be available to you during this test. To access these reference materials, click on the reference materials icon located in the lower left corner of the screen.

You may work on and complete the selected-response questions and the constructed-response assignment in any order that you choose. Be sure to allocate your time carefully so that you are able to complete the entire test within the testing session.

Use of any other type of calculator or outside reference materials during the testing session is prohibited.

Sample Selected-Response Questions

Competency 0001 
Apply knowledge of the laws of motion and the application of kinematics in one and two dimensions.

1. An object is launched at a velocity of 35 meters per second in a direction that makes an angle of 25degrees above horizontal, level ground. Which of the following values is closest to the time the object spends in the air?

  1. 1.5 seconds
  2. 3.0 seconds
  3. 6.5 seconds
  4. 7.1 seconds

Correct Response: B. The vertical component of initial velocity is v subscript y equals 35 sine of 25 equals 14.8 meters per second. The time to maximum height when the vertical velocity is zero is t equals v subscript y divided by g equals 14.8 divided by 9.8 equals 1.5 seconds. On level ground, the total time in the air is double this time, 3.0 seconds.

Competency 0001 
Apply knowledge of the laws of motion and the application of kinematics in one and two dimensions.

2. An object is thrown straight up and is caught at the same point from which it was released. The magnitude of the vertical displacement on the way up is delta y subscript up. The magnitude of the vertical displacement on the way down is delta y subscript down. If air resistance is ignored, which of the following equations would correctly compare the displacement of the object on the way up and on the way down?

  1. delta y subscript up = negative delta y subscript down
  2. 2 delta y subscript up = delta y subscript down
  3. delta y subscript up = delta y subscript down
  4. delta y subscript up = negative 2 delta y subscript down

Correct Response: A. Ignoring air resistance, the displacement of the object on the way up will be equal in magnitude to the displacement on the way down if it is caught at the same location as it was released. This is because both the change in speed and the acceleration of the object in each part of the motion are identical. Since displacement is a vector, the values will have opposite signs.

Competency 0002 
Apply knowledge of systems undergoing rotational motion, simple harmonic motion, and systems in equilibrium.

3. Engineers need to determine the torque due to friction on an old bearing in an axle. To spin the bearing at a constant rotation rate, they determine that a constant force of 0.40 Newtons needs to be applied perpendicular to the axle and 14 centimeters from the center of the axle. Which of the following values is closest to the torque due to friction in the bearing of the axle?

  1. 0.028 Newton meters
  2. 0.056 Newton meters
  3. 0.35 Newton meters
  4. 2.9 Newton meters

Correct Response: B. The rotation rate of the axle is constant while the applied force is engaged; therefore, the applied toque must be equal in magnitude and opposite in direction to the frictional torque. The applied torque is perpendicular to the axle and 0.14 meters from the center axis. The torque applied, which equals the magnitude of frictional torque, is 0.40 Newtons times 0.14 meters times sine of 90 equals 0.056 Newton meters.

Competency 0003 
Apply knowledge of principles of the conservation of energy and momentum.

4. Students are asked to explore the conservation of angular momentum for a pendulum. Which of the following guiding questions would be most appropriate for this investigation?

  1. What are the units for angular momentum?
  2. How are forces affecting the motion of the pendulum?
  3. How are torque and angular momentum related to each other?
  4. What are the acceleration and velocity of the pendulum during the motion?

Correct Response: C. When exploring conservation principles, an understanding of the quantities that cause changes is the most important approach to apply when developing a guiding question. The quantity that causes changes in angular momentum is the net, external torque. Understanding how torque and angular momentum are related should be the focus of the guiding question for such an investigation.

Competency 0004 
Apply knowledge of electric charge, electric fields, and electric circuits.

5. A 0.020 Coulomb point charge is placed in a uniform electric field whose magnitude is 400 Newtons per Coulomb. Which of the following values represents the force on this point charge?

  1. 8 Newtons
  2. 2000 Newtons
  3. 8000 Newtons
  4. 20,000 Newtons

Correct Response: The force on a point charge in a uniform electric field is given as F equals q E equals 0.020 Coulombs times 400 Newtons per Coulomb equals 8 Newtons.

Competency 0005 
Apply knowledge of characteristics of magnetic fields, magnetic interactions with charges, and principles of electromagnetic induction.

6. One way that radio waves differ from visible light waves is that radio waves:

  1. travel slower.
  2. have greater frequency.
  3. travel faster.
  4. have a smaller frequency.

Correct Response: D. Radio waves differ from visible light waves in both wavelength and frequency. All types of electromagnetic waves travel at the same speed of light, given by c = lambda f. Radio waves have wavelengths of several centimeters or greater, and visible light waves have wavelengths of just a few hundred nanometers. Radio waves must have smaller frequencies when compared to visible light.

Competency 0006 
Apply knowledge of waves and their properties.

7. As light passes from material A into material B, the light bends away from the normal to the surface. Which of the following statements is most accurate in this situation?

  1. The light became polarized.
  2. The speed of the light increased.
  3. Material A must be more opaque than material B.
  4. Material A has a smaller index of refraction than material B.

Correct Response: B. As light passes to and from materials with different indices of refraction, the light is refracted, or bends relative to the normal to the surface boundary. Light will bend away from the normal when the material the light is entering has a lower index of refraction, given as n = c divided by v, where c is the speed of light in vacuum and v is the speed of light in any medium. Material B must have a smaller refractive index and larger velocity for the light.

Competency 0007 
Apply knowledge of kinetic theory and the laws of thermodynamics.

8. The temperature of a material is most closely related to the material's:

  1. binding energy in the nucleus.
  2. kinetic energy of the molecules.
  3. mechanical energy of the electrons.
  4. potential energy in the bonds of the molecules.

Correct Response: B. According to the kinetic theory of matter, the temperature of a bulk material is modelled by the statistical average of the kinetic energy of the material's molecules.

Competency 0008 
Apply knowledge of the quantum theory of light and matter.

9. Which of the following observable phenomena can best be described as evidence of the particle nature of light?

  1. interference
  2. diffraction
  3. polarization
  4. scattering

Correct Response: D. Scattering describes the process whereby moving particles or radiation are deflected or scattered in various directions from their original trajectory within the medium in which they travel. The scattering trajectories and energies cannot be adequately explained or predicted solely by the wave nature of light. Instead, scattering trajectories and energies can be better predicted by modeling the photons as particles. Predicting the angular distribution and energy shift of scattered photons observed from the Compton effect requires that photons' momentum and energy be modelled as particles.

Competency 0009 
Apply knowledge of atomic structure and nuclear physics.

10. Barium-137 nuclei have a half-life of approximately 2.5 minutes. Which of the following fractions of the original sample of barium-137 should remain after 10 minutes?

  1. 1 over 25
  2. 1 over 16
  3. 1 over 10
  4. 2 over 5

Correct Response: B. Barium-137 has a half-life of 2.5 minutes. The amount of barium should be halved four times: 1 half times 1 half times 1 half times 1 half = 1 sixteenth of the original amount of barium remains after 10 minutes.