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Midterm Exam 09-10 C

Modified True/False
Indicate whether the sentence or statement is true or false.
 

1. 
The property of matter that resists a change in motion is called inertia.

 

2. 
The pressure you exert on the floor decreases when you stand on your toes because the area on which you exert force decreases.

 

3. 
When you raise your leg, the knee acts as a fulcrum for the upper leg.

 

4. 
Wind blowing across the top of a chimney helps to draw air up the chimney. This is an example of Bernoulli’s principle.

 

5. 
The upper layer of Earth is broken into more than a dozen continents that move very slowly in various directions.

 

6. 
More force is required to lift an object in water than on land because of the buoyant force of the water.

 

7. 
Your jaw and teeth act together as a simple machine.

 

8. 
Holding a 25-N bag of sugar 1 meter above the floor requires 25 joules of work.

 

9. 
The volume of liquid displaced by a floating cork is less than the volume of the object.

 

10. 
Air enters your lungs when you inhale because the pressure inside your lungs and the pressure outside are balanced.

 

11. 
According to Newton’s second law of motion, force equals mass times weight.

 

12. 
The force that keeps a satellite in Earth orbit is always directed away from the center of Earth.

 

13. 
The work done by a machine is called the output work.

 

14. 
Hydraulic systems use two pistons with different surface areas to lift heavy objects.

 

15. 
The air pressure at an altitude of 3 km is less than the air pressure at 1 km.

 

16. 
A child riding on a merry-go-round is accelerating because his direction is changing.

 

17. 
The force of gravity decreases as the masses of objects increase.

 

18. 
Efficiency compares the output work to the output force.

 

19. 
Newton’s third law of motion explains that forces act alone.

 

20. 
Motion is measured relative to a reference point.

 

21. 
Unbalanced forces maintain motion at constant velocity.

 

22. 
Friction depends on the types of surfaces involved and how hard the surfaces push together.

 

23. 
A rocket will move upward as long as the thrust is greater than the pull of gravity.

 

24. 
A straight line on a motion graph indicates constant speed.

 

25. 
A wheel and axle is a compound machine.

 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

26. 
The tendency of an object to resist change in its motion is known as
a.
mass.
b.
inertia.
c.
force.
d.
balance.
 

27. 
The upper layer of Earth consists of more than a dozen major pieces called
a.
units.
b.
plates.
c.
continents.
d.
tectonics.
 

28. 
An object that travels around another object in space is called a
a.
projectile.
b.
inertia.
c.
mass.
d.
satellite.
 

29. 
A train that travels 100 kilometers in 4 hours is traveling at what average speed?
a.
50 km/h
b.
100 km/h
c.
2 km/h
d.
25 km/h
 

30. 
When the only force acting on a falling object is gravity, the object is said to be
a.
stationary.
b.
decelerating.
c.
in free fall.
d.
a projectile.
 

31. 
A ship stays afloat as long as the buoyant force is
a.
less than the ship’s weight.
b.
greater than the ship’s weight.
c.
less than the ship’s speed.
d.
greater than the ship’s speed.
 

32. 
What scientific rule states that the pressure exerted by a moving stream of fluid is less than the pressure of the surrounding fluid?
a.
Archimedes’ principle
b.
Pascal’s principle
c.
Bernoulli’s principle
d.
Newton’s third law of motion
 

33. 
The basic SI unit of length is the
a.
meter.
b.
foot.
c.
inch.
d.
mile.
 

34. 
The ideal mechanical advantage for an inclined plane is equal to the length of the incline divided by the
a.
mass of the incline.
b.
slope of the incline.
c.
height of the incline.
d.
angle of the incline.
 

35. 
The force of gravity on a person or object at the surface of a planet is known as
a.
mass.
b.
inertia.
c.
air resistance.
d.
weight.
 

36. 
The pressure exerted by a moving stream of fluid
a.
is greater than the pressure of the surrounding fluid.
b.
is less than the pressure of the surrounding fluid.
c.
depends on the nature of the fluid.
d.
depends on the volume of the fluid.
 

37. 
If a bicyclist travels 30 kilometers in two hours, her average speed would be
a.
30 km/h.
b.
60 km/h.
c.
15 km/h.
d.
2 km/h.
 

38. 
Which of the following is an example of rolling friction?
a.
your shoes on a sidewalk as you walk
b.
bike tires on the road as you ride
c.
a boat on the water as it sails
d.
two hands rubbing together
 

39. 
What do machines do?
a.
change force or distance
b.
increase work
c.
decrease work
d.
eliminate friction
 

40. 
If the speed of an object does NOT change, the object is traveling at a
a.
constant speed.
b.
average speed.
c.
increasing speed.
d.
decreasing speed.
 

41. 
Force = mass x
a.
speed.
b.
motion.
c.
acceleration.
d.
inertia.
 

42. 
Work = force •
a.
energy.
b.
velocity.
c.
distance.
d.
mass.
 

43. 
In graphing motion, the steepness of the slope depends on
a.
how quickly or slowly the object is moving.
b.
how far the object has moved.
c.
the velocity of the object.
d.
the direction the object is moving.
 

44. 
The product of an object’s mass and velocity is called its
a.
inertia.
b.
momentum.
c.
acceleration.
d.
force.
 

45. 
Which of these is an example of deceleration?
a.
a bird taking off for flight
b.
a baseball released by a pitcher
c.
a car approaching a red light
d.
an airplane turning to change its course
 

46. 
In physical science, a push or a pull is called a(n)
a.
force.
b.
acceleration.
c.
inertia.
d.
motion.
 

47. 
What does a hydraulic system do?
a.
decrease pressure
b.
increase velocity
c.
multiply force
d.
reduce inertia
 

48. 
When an object’s distance from another object is changing,
a.
it is in motion.
b.
it is speeding.
c.
it has a high velocity.
d.
it is accelerating.
 

49. 
Forces can be added together only if they are
a.
acting on the same object.
b.
balanced forces.
c.
unaffected by gravity.
d.
substantial.
 

50. 
The force that one surface exerts on another when the two rub against each other is called
a.
friction.
b.
acceleration.
c.
inertia.
d.
gravity.
 

51. 
Which body parts are shaped like wedges?
a.
muscles
b.
tendons
c.
incisors
d.
bones in your legs
 

52. 
The amount of matter in an object is called its
a.
inertia.
b.
mass.
c.
force.
d.
balance.
 

53. 
To determine the acceleration rate of an object, you must calculate the change in velocity during each unit of
a.
speed.
b.
time.
c.
motion.
d.
deceleration.
 

54. 
The mass per unit volume of a substance is its
a.
density.
b.
buoyancy.
c.
weight.
d.
fluid pressure.
 

55. 
Bernoulli’s principle explains
a.
hydraulic brakes.
b.
buoyancy.
c.
momentum.
d.
flight.
 

56. 
When you know both the speed and direction of an object’s motion, you know the
a.
average speed of the object.
b.
acceleration of the object.
c.
distance the object has traveled.
d.
velocity of the object.
 

57. 
When you raise or lower a flag on a flagpole, you are using a
a.
wheel and axle.
b.
pulley.
c.
wedge.
d.
inclined plane.
 

58. 
Work is measured in
a.
meters.
b.
pounds.
c.
joules.
d.
newtons.
 

59. 
Gallons, inches, and pounds are all
a.
distances.
b.
reference points.
c.
units.
d.
velocities.
 

60. 
Without friction there would be
a.
less machine efficiency.
b.
greater output work than input work.
c.
greater input work than output work.
d.
equal input and output work.
 

61. 
What scientific rule states that the buoyant force on an object is equal to the weight of the fluid displaced by the object?
a.
Archimedes’ principle
b.
Pascal’s principle
c.
Bernoulli’s principle
d.
Newton’s third law of motion
 

62. 
A substance whose shape can easily change is a
a.
solid.
b.
powder.
c.
fluid.
d.
metal.
 

63. 
The mechanical advantage of a machine that changes the direction of force only is
a.
1
b.
less than 1.
c.
greater than 1.
d.
zero.
 

64. 
Which type of substance does Pascal’s principle deal with?
a.
solids
b.
fluids
c.
powders
d.
metals
 

65. 
The momentum of an object is in the same direction as its
a.
force.
b.
acceleration.
c.
velocity.
d.
inertia.
 

66. 
According to the law of conservation of momentum, when two objects collide in the absence of friction,
a.
velocity decreases.
b.
velocity increases.
c.
momentum is not lost.
d.
only the object with the larger mass continues on.
 

67. 
A ramp is an example of a simple machine called a(n)
a.
inclined plane.
b.
wedge.
c.
lever.
d.
pulley.
 

68. 
For work to be done on an object, such as pushing a child on a swing,
a.
some force need only be exerted on the object.
b.
the object must move some distance as a result of a force.
c.
the object must move, whether or not a force is exerted on it.
d.
the object must move a distance equal to the amount of force exerted on it.
 

69. 
Which of the following is true of the buoyant force?
a.
It acts in the downward direction.
b.
It acts with the force of gravity.
c.
It acts in the upward direction.
d.
It makes an object feel heavier.
 

70. 
Most machines in your body, which consist of bones and muscles, are
a.
wedges
b.
levers.
c.
pulleys.
d.
compound machines.
 

71. 
The braking system on a car is an example of
a.
a hydraulic system.
b.
buoyancy.
c.
Bernoulli’s principle.
d.
Newton’s third law of motion.
 

72. 
The rate at which velocity changes is called
a.
speed.
b.
direction.
c.
acceleration.
d.
motion.
 

73. 
The force that pulls falling objects toward Earth is called
a.
gravity.
b.
free fall.
c.
acceleration.
d.
air resistance.
 

74. 
Air resistance is a type of
a.
motion.
b.
acceleration.
c.
velocity.
d.
friction.
 

75. 
A place or object used for comparison to determine if something is in motion is called
a.
a position.
b.
a reference point.
c.
a constant.
d.
velocity.
 

76. 
An ideal machine would have an efficiency of
a.
1 percent.
b.
10 percent.
c.
50 percent.
d.
100 percent.
 

77. 
In an acceleration graph showing speed versus time, a straight line shows the acceleration is
a.
decreasing.
b.
increasing.
c.
changing.
d.
constant.
 

78. 
If tight scissors have an efficiency of 50 percent, how much of your work is wasted overcoming friction?
a.
all of it
b.
none of it
c.
one half
d.
10 percent
 

79. 
A unit of pressure is called a
a.
bernoulli.
b.
pascal.
c.
pound.
d.
meter.
 

80. 
Air pressure exerted equally on an object from different directions is
a.
balanced pressure.
b.
gravitational pressure.
c.
fluid pressure.
d.
constant pressure.
 

81. 
The law of universal gravitation states that any two objects in the universe, without exception,
a.
attract each other.
b.
repel each other.
c.
combine to provide a balanced force.
d.
create friction.
 

82. 
Speed equals distance divided by
a.
time.
b.
velocity.
c.
size.
d.
motion.
 

83. 
The fixed point that a lever pivots around is called the
a.
axle.
b.
pulley.
c.
gear.
d.
fulcrum.
 

84. 
A machine that utilizes two or more simple machines is called a
a.
combination machine.
b.
compound machine.
c.
mechanical machine.
d.
mixed machine.
 

Completion
Complete each sentence or statement.Use the word bank below to fill in the blanks. Each word is used once and only once.
Joule            Inclined plane            actual            wedge            constant           
mass            wheel and axle            satellite      velocity      speed           
100      air resistance            buoyant force            deceleration            direction
     
input            friction            net            dense            increases      km/h     

motion            increases            compound            distance      negative     
screw            balances            stationary            lever            meter           
fluid            km/h            opposite            lower            pressure
 

85. 
A screwdriver is a simple machine called a(n) ____________________.
 

 

86. 
A reference point is assumed to be ____________________, or not moving.
 

 

87. 
The force of gravity between you and Earth is greater than the force of gravity between you and a car because Earth has more ____________________ than the car.
 

 

88. 
The basic SI unit of length is the ____________________.
 

 

89. 
The overall force on an object after all the forces are added together is called the ____________________ force.
 

 

90. 
When force is applied to a confined fluid, an increase in ____________________ is transmitted equally to all parts of the fluid.
 

 

91. 
A jar lid is an example of a simple machine called a(n) ____________________.
 

 

92. 
A change in an object’s position relative to a reference point is called ____________________.
 

 

93. 
Wet pavement is more slippery than dry pavement because the force needed to overcome ____________________ friction is less than the force needed to overcome sliding friction.
 

 

94. 
Acceleration is the rate of change in ____________________.
 

 

95. 
A newton-meter is a measure of work also known as the ____________________.
 

 

96. 
Speed that does not change is referred to as ____________________ speed.
 

 

97. 
The moon is a natural ____________________ of Earth.
 

 

98. 
A speed of 15 kilometers per hour is abbreviated as 15 ____________________.
 

 

99. 
A ramp in a parking garage is an example of a simple machine called a(n) ____________________.
 

 

100. 
As you wave your hand at the wrist, your hand is acting as a simple machine called a(n) ____________________.
 

 

101. 
A simple machine makes work easier by multiplying force or ____________________, or by changing direction.
 

 

102. 
If a ship has an acceleration of 3 km/h2, its speed is expressed in the unit ____________________.
 

 

103. 
Chocolate syrup sinks in milk because chocolate syrup is more ____________________ than milk.
 

 

104. 
A block of wood is placed in a jar of water. According to Archimedes’ principle, the ____________________ on the block is equal to the weight of the displaced fluid.
 

 

105. 
When ____________________ equals the force of gravity on a falling object, the object reaches terminal velocity.
 

 

106. 
The set of gears on a bicycle wheel is classified as a(n) ____________________ machine.
 

 

107. 
____________________ occurs when an object slows down.
 

 

108. 
The force of gravity is responsible for continuously changing the ____________________ in which a satellite moves.
 

 

109. 
The efficiency of an actual machine is always less than ____________________%.
 

 

110. 
The momentum of a roller skater is not conserved because ____________________ acts on the skates.
 

 

111. 
If the action force of a bat striking a ball accelerates the ball in one direction, the reaction force accelerates the bat in the ____________________ direction.
 

 

112. 
The motion of a car stopping at a traffic light is an example of a ____________________ acceleration, also called deceleration.
 

 

113. 
The ____________________ mechanical advantage of a machine cannot be predicted in advance because it depends on the efficiency of the machine.
 

 

114. 
As the distance between two objects decreases, the gravitational force between them ____________________.
 

 

115. 
The force applied to a machine is called the ____________________ force.
 

 

116. 
According to Bernoulli’s principle, the pressure in a moving stream of fluid is ____________________ than the pressure of the surrounding fluid.
 

 

117. 
The pressure inside an air mattress ____________________ the pressure caused by your weight when you lie on it.
 

 

118. 
Water pressure ____________________ with depth.
 

 

119. 
As you bite into a peach, your front teeth act as a simple machine called a(n) ____________________.
 

 

120. 
The distance traveled by a moving object per unit of time is called ____________________.
 

 



 
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