Practice Test: Forces And Motion

20 Questions | Total Attempts: 1429

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Practice Test: Forces And Motion

Sample test preparation for Forces and Motion unit.


Questions and Answers
  • 1. 
    The free-body diagram below represents a 2000-kg elevator. What is the motion of the elevator if the tension in the cable is 1.96 ´ 104 N? (Assume 3 significant digits.)
    • A. 

      The elevator might be accelerating upward.

    • B. 

      The elevator might be accelerating downward.

    • C. 

      The elevator must be at rest.

    • D. 

      The elevator cannot be undergoing uniform motion.

    • E. 

      The elevator must not be accelerating.

  • 2. 
    • A. 

      The amount of material of which you are composed

    • B. 

      The gravitational force which Earth exerts on you

    • C. 

      The gravitational force you exert on Earth

    • D. 

      The force you exert on a set of bathroom scales

    • E. 

      None of the above

  • 3. 
    The value of "g" at the surface of Mars is 3.7 N/kg. How much would a 60.0-kg person weigh at an altitude above the Martian surface equivalent to the planet's radius?
    • A. 

      2.2 x 102 N

    • B. 

      1.6 x 102 N

    • C. 

      1.1 x 102 N

    • D. 

      56 N

    • E. 

      28 N

  • 4. 
    • A. 

      A

    • B. 

      B

    • C. 

      C

    • D. 

      D

    • E. 

      E

  • 5. 
    The gravitational field strength of Earth
    • A. 

      Has a value of exactgly 9.8 N/kg [down] at all locations on its surface

    • B. 

      Is greater at the equator than at the poles

    • C. 

      Is smallest at the peak of Mount Everest, the highest elevation

    • D. 

      Is largest at the deepest spot on the ocean floor

    • E. 

      Is largest at the poles

  • 6. 
    If you weighed 112 N on the Moon where g = 1.6 N/kg, how much would you weigh on Earth?
    • A. 

      1.1 x 102 N

    • B. 

      1.7 x 104 N

    • C. 

      6.9 x 102 N

    • D. 

      1.1 x 104 N

    • E. 

      6.9 x 103 N

  • 7. 
    According to Newton's law of universal gravitation, the gravitational force of attraction between two objects would be
    • A. 

      Half as strong if they're moved twice as far apart

    • B. 

      Twice as strong if they're moved half as far apart

    • C. 

      Four times as strong if they're moved twice as far apart

    • D. 

      Four times as strong if they're moved half as far apart

    • E. 

      Twice as strong if they're moved twice as far apart

  • 8. 
    What would the gravitational field strength be on a planet with half Earth's mass and half its radius?
    • A. 

      78.4 N/kg

    • B. 

      39.2 N/kg

    • C. 

      19.6 N/kg

    • D. 

      9.8 N/kg

    • E. 

      4.9 N/kg

  • 9. 
    Consider two planets, A and B. Planet A has half the mass and half the radius of planet B. The ratio of gA : gB would be
    • A. 

      2 : 1

    • B. 

      1 : 2

    • C. 

      4 : 1

    • D. 

      1 : 4

    • E. 

      1 : 1

  • 10. 
    Study the force system diagram pictured below and select the factor which would NOT influence the amount of kinetic friction.
    • A. 

      Object's mass

    • B. 

      Coefficient of kinetic friction

    • C. 

      Normal force

    • D. 

      Applied force

    • E. 

      Gravitational field strength

  • 11. 
    The coefficient of friction stems from the
    • A. 

      Nature of the two surfaces in contact

    • B. 

      Mass of the object

    • C. 

      Strength of the applied force

    • D. 

      Strength of the normal force

    • E. 

      Strength of the gravitational force

  • 12. 
    If the strength of the frictional force is equal to the applied force and oppositely directed, and assuming that all other forces may be ignored, the object
    • A. 

      Must be at rest

    • B. 

      Must be just about to move

    • C. 

      May be at rest or moving at uniform velocity

    • D. 

      Must be accelerating

    • E. 

      Must be slowing down

  • 13. 
    A chalk brush sits on a metre stick as pictured in the diagram. As one end of the metre stick is elevated, the chalk brush eventually begins to slide. Why?
    • A. 

      The coefficient of friction changes.

    • B. 

      The gravitational force on the brush changes.

    • C. 

      The normal force on the brush changes.

    • D. 

      The gravitational force begins to act along the metre stick.

    • E. 

      An applied force is created.

  • 14. 
    A 425-g model rocket is accelerated upward at 86 m/s2 by its engine. What is the value of the force exerted by the engine on the rocket?
    • A. 

      41 N [up]

    • B. 

      41 N [down]

    • C. 

      37 N [up]

    • D. 

      32 N [up]

    • E. 

      32 N [down]

  • 15. 
    A 4.0-kg object, A, and a 2.0-kg object, B, are connected with a rope. A force is applied to another rope attached to the 2.0-kg object that pulls both A and B along a horizontal surface. Which of the following statements is true?
    • A. 

      The force that B exerts on A is greater than the force that A exerts on B.

    • B. 

      The force that A exerts on B is greater than the force that B exerts on A.

    • C. 

      The force that B exerts on A is equal to the force that A exerts on B provided that the system slides with uniform motion.

    • D. 

      The force that B exerts on A is equal to the force that A exerts on B regardless of the motion of the system.

    • E. 

      The sum of the applied force and the force that B exerts on A is equal to the force that A exerts on B.

  • 16. 
    A 1.5-kg cart is pulled with a force of 7.3 N at an angle of 40° above the horizontal. If a kinetic friction force of 3.2 N acts against the motion, the cart’s acceleration along the horizontal surface will be
    • A. 

      1.0 m/s2

    • B. 

      1.6 m/s2

    • C. 

      2.4 m/s2

    • D. 

      2.7 m/s2

    • E. 

      5.0 m/s2

  • 17. 
    A 1.8-kg object is pulled along the floor with a force of 7.0 N acting horizontally. If the object accelerates at 2.4 m/s2, how much kinetic friction is acting?
    • A. 

      30 N

    • B. 

      11 N

    • C. 

      8.3 N

    • D. 

      7.8 N

    • E. 

      2.7 N

  • 18. 
    Which of the following statements concerning friction is true?
    • A. 

      The frictional force always acts oppositely to the applied force.

    • B. 

      For two given surfaces, the coefficient of static friction is generally greater than the coefficient of kinetic friction.

    • C. 

      Friction is a force which is unavoidable and serves no practical purpose.

    • D. 

      Two very highly-polished surfaces in contact with one another will have very little friction between them.

    • E. 

      Friction always acts in the direction of motion.

  • 19. 
    If all other forces can be ignored and the strength of the frictional force is greater than the applied force and oppositely directed, the object
    • A. 

      Could be speeding up or slowing down

    • B. 

      Must be speeding up

    • C. 

      Must be slowing down

    • D. 

      Could be moving with uniform motion

    • E. 

      Could be stopped

  • 20. 
    The free-body diagram of a block being pushed up a rough ramp is best represented by
    • A. 

      A

    • B. 

      B

    • C. 

      C

    • D. 

      D

    • E. 

      E