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```									Chapter 11 Test: Motion
In the space provided, write the letter of the term or phrase that best completes each statement or best

_____ 1. The distance traveled by an object divided by the time it takes to travel
that distance is called
a. average velocity.                         c. average acceleration.
b. average speed.                            d. negative acceleration.

_____ 2. On a distance vs. time graph, the line of an object at rest is a
a. curved line with a slope of zero.
b. flat line with a slope of zero.
c. jagged line with a negative slope.
d. curved line with a positive slope.

_____ 3. The difference between speed and velocity is that velocity includes
a. direction.                         c. time.
b. distance.                          d. weight.

_____ 4. An example of helpful friction is
a. car tires wearing out.                     c. writing on paper with a pen.
b. getting holes in your socks.               d. scraping your knee on the floor.

_____ 5. Friction is defined as the
a. force that opposes motion between two surfaces that are touching.
b. rate at which velocity changes.
c. resistance of an object to a change in its velocity.
d. speed of an object in a particular direction.

_____ 6. An object is in motion when
a. the net force acting on the object is zero.
b. friction occurs.
c. the object’s displacement is greater than the distance traveled.
d. the object changes position relative to a frame of reference.

_____ 7. Force is a quantity made up of
a. weight and speed.                                 c. time and acceleration.
b. magnitude and direction.                          d. mass and velocity.

_____ 8. Which is an example of balanced forces acting on an object?
a. a kangaroo jumping                         c. a person standing on the ground
b. a car turning a corner                     d. a person pushing a sofa

_____ 9. Acceleration is defined as the change in velocity divided by
a. speed.                               c. time.
b. final velocity.                      d. distance.
_____ 10. Which is an example of kinetic friction?
a. friction between a car’s windshield and the air as you drive into the wind
b. friction between your shoes and the ground when you stand still
c. friction between a sticky note and the page of a book as it marks your place
d. friction between your skin and a pencil as it rests in your palm

_____ 11. In order to determine speed, you must know
a. only time.                        c. both time and distance.
b. only distance.                    d. neither time nor distance.

_____ 12. An airplane is flying at 635 mi/h at an altitude of 35,000 ft. It is currently over Kansas
and is approximately 16 min ahead of its scheduled arrival time. What is its velocity?
a. 635 mi/h          c. 35,000 ft/s
b. 16 mi/min         d. can’t be determined without knowing about its direction.

_____ 13. Which of the following does not indicate velocity?
a. 14 ft/s SSE
b. 40 mi/h toward the town square along the main street
c. 80 km/h going from New York toward New Jersey
d. 28 miles from Los Angeles to Catalina Island

_____ 14. When an object slows down, its acceleration is
a. positive.                           c. negative.
b. centripetal.                        d. constant.

_____ 15. If the net force acting on a stationary object is zero, then the object will
a. accelerate in the direction of the strongest force.
b. remain at rest.
c. begin moving backwards.
d. decelerate at a steady rate of speed.

_____ 16. Displacement
a. must be in a particular direction.      b. is the change in position of an object.
c. must be a straight line.                d. All of the above

_____ 17. The force of gravity, the electromagnetic force, the strong nuclear force, and the weak
nuclear force are considered
a. centripetal forces.                         c. resultant forces.
b. frames of reference.                        d. fundamental forces.

_____ 18. On a speed vs. time graph, constant acceleration is represented by a
a. straight line.                               c. jagged line.
b. slightly sloped line.                        d. steeply sloped line.
_____ 19. The friction between the bristles of your toothbrush and the surfaces of your teeth is an
example of
a. rolling friction.                            c. helpful friction.
b. static friction.                             d. All of the above

_____ 20. Which straight-line acceleration indicates an increase in speed?
a. 0 m/s2                                       c. 4 m/s2
b. –15 m/s 2
d. All of the above
Read each statement, and write in the blank the word or words that best completes the statement.

21. When an object covers equal distances in equal amounts of time, it is moving at a(n)
_______________________ speed.

22. Acceleration is the rate at which _______________________ changes.

23. In order to determine if an object is moving, you must observe the object in relation to a(n) frame of
________________.

24. Speed measured in an infinitely small time interval is _______________________.

25. On a distance vs. time graph, time is represented on the x-axis as the ______________ variable.

26. A(n) _____________ line on a velocity vs. time graph means that the velocity changes by the same
amount over each time interval.

27. The friction between a book at rest and the desk it is lying on is an example of ______________
friction.

28. Baseball players wear batting gloves to increase _______________________.

29. An action exerted on a body to change its state of rest or motion is a(n) _______________.

30. In the acceleration equation, the change in an object’s velocity is represented by the symbol ____.

31. Because the speed of an object can change from one instant to the next, dividing the total distance
covered by the time of travel gives _______________________.

32. Velocity describes both speed and _______________________.

33. Acceleration can be determined from a velocity vs. time graph by calculating the line’s __________.

34. One way to reduce friction in a car engine is to add a(n) ______________such as oil or grease.

35. The change in the position of an object is called _______________________.

36. On a distance vs. time graph, distance is usually the ______________ variable.

37. The force of gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force
are examples of ____________________ forces.

38. The combination of all forces acting on an object is the __________ force.

39. When the net force on an object is greater than __________, the object will accelerate in the
direction of the greater force.

40. Static friction is usually greater than ____________friction.
Friction is a force that we experience every day. Even though we may not always be aware of
friction, our interaction with this force has a “Dr. Jekyll and Mr. Hyde” nature. In other words, like
Dr. Jekyll, friction sometimes makes our lives easier and safer; at other times, friction, like Mr.
Hyde, interferes with our activities and devices used to perform them. For instance, we can place
an object, such as a can of soda, on an inclined slope. When the soda does not slide off, we
appreciate the force of friction, especially if the day is hot and we are thirsty. We can also thank
friction when we need to make an emergency stop while driving in a car. In this case, friction—the
force applied by the car’s brakes to its wheels—is responsible for stopping the vehicle. On the
other hand, friction can make our lives more difficult by hindering our progress. For example, as
cars, trains, and airplanes move, they experience a type of friction known as air resistance.
Because the molecules in air oppose the movement of these vehicles, extra energy or fuel is
needed to maintain a desired speed. When we use extra fuel, we waste limited natural resources
and spend more money, which may also be a limited resource. In this case, friction, like Mr.
Hyde, is rather disruptive and disagreeable.
In the space provided, write the letter of the term or phrase that best completes each statement or best

_____ 41. What is the main idea of this passage?
A. to tell a story about Dr. Jekyll and Mr. Hyde
B. to identify numerous examples of friction
C. to illustrate the positive and negative aspects of friction
D. to encourage conservation of energy resources

_____ 42. In this passage, the word devices means
A. sinister plans. B. virtues.       C. inclinations.              D. gadgets.

_____ 43. In this passage, the word hindering means
A. opposing.       B. improving.     C. mending.                   D. shaping.

_____ 44. The metaphor about Dr. Jekyll and Mr. Hyde is used to
A. emphasize the contrast between different features of friction.
B. clarify the main point of the story by means of a distraction.
C. inspire the audience to read more books.
D. identify actual properties of friction.

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