Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
| 1. | The
force that resists the motion of objects or surfaces in contact with one another is called ____
force. a. | inertial | b. | frictional | c. | normal | d. | net | | |
|
|
| 2. | The
force of friction between two surfaces can be reduced by all of the following
EXCEPT: a. | changing rolling
friction to sliding friction. | b. | changing sliding friction to rolling
friction. | c. | changing static friction to kinetic
friction. | d. | sanding rough surfaces smoother. | | |
|
|
| 3. | Two
moving surfaces are in contact with one another. The force of friction between the surfaces can be
changed by all of the following methods EXCEPT: a. | placing lubrication between the
surfaces. | b. | changing the types of surfaces. | c. | changing the
force used to move the surfaces. | d. | altering the force pushing the two surfaces
together. | | |
|
|
| 4. | To
overcome static friction to start an object sliding on a level surface, a 100-newton force is used.
The magnitude of the force needed to keep the object the sliding is: a. | more than 100
newtons. | b. | equal to 100 newtons. | c. | less than 100
newtons. | d. | unknown using the given information. | | |
|
|
| 5. | Of
the following, the statement about friction which is NOT true is: a. | friction is
always present. | b. | friction can be useful. | c. | friction can be
harmful. | d. | friction can be eliminated. | | |
|
|
| 6. | As
Joshua accelerates in his pickup truck at 2.0m/sec2, a 200-kilogram box in the back does
not slide. The force of friction that must act on the box to keep it from slipping in the back of the
truck is ____ newtons.
|
|
| 7. | The
diagram below represents a box sliding down an incline:
The force of friction acting on the box is directed
toward:
|
|
| 8. | Pulling on a rope with a force of 100 newtons at an angle  of 30
degrees, Cheung pulls a box across a surface at a constant speed:
The magnitude of the frictional force resisting the motion is ____
newtons.
|
|
| 9. | The
line about which an object turns is called the: a. | torque. | b. | axis of
rotation. | c. | radius. | d. | lever
arm. | | |
|
|
| 10. | As
the force applied to a rotating object is moved farther from the axis of rotation, the torque created
by the force: a. | increases. | b. | decreases. | c. | is always
clockwise. | d. | is always perpendicular to the lever
arm. | | |
|
|
| 11. | Aaron
applies a 70.0-newton force to the handle of a wrench at a distance of 0.350 meters from the nut on
the axle of his bicycle wheel. The amount of torque applied to the nut is ____
newton-meters. a. | 0.005 | b. | 24.5 | c. | 70.35 | d. | 200 | | |
|
|
| 12. | The
diagram represents a lever to which forces are applied:
To create rotational equilibrium, the force exerted at the left end of
the lever must be ____ newtons.
|
|
| 13. | Juan
and his younger sister Ana are able to balance when seated on a see-saw. Juan weighs 800 newtons and
sits 2.0 meters from the balance point. Ana weighs 400 newtons.
To create rotational equilibrium, the distance she must sit from the
balance point is ____ meter(s).
|
|
| 14. | The
parabolic path followed by a projectile is referred to as the: a. | range. | b. | trajectory. | c. | circumference. | d. | ellipse. | | |
|
|
| 15. | The
distance a projectile travels horizontally in the air may be called its: a. | trajectory. | b. | range. | c. | parabola. | d. | height. | | |
|
|
| 16. | Of
the following, the one that would NOT be considered a projectile is a: a. | crow flying
between trees. | b. | football thrown by a high school
quarterback. | c. | tennis ball hit by a star tennis
player. | d. | fox jumping over a wall. | | |
|
|
| 17. | Jennifer and Tamar throw a snowballs at the same time horizontally from a height of
1.5 meters. Jennifer throws hers at a speed of 6.0 meters per second. If Tamar throws hers at 12
meters per second, her snowball will: a. | travel the same distance as Jennifer’s before hitting the
ground. | b. | hit the ground later than
Jennifer’s. | c. | travel the half the distance as Jennifer’s before hitting
the ground. | d. | hit the ground at the same time as
Jennifer’s. | | |
|
|
| 18. | A
stunt car driver traveling at 30 meters per second drives his car off a 20 meter high cliff as
illustrated in the diagram:
How far from the base of the cliff does the car hit? a. | 41
meters | b. | 61 meters | c. | 82
meters | d. | 122 meters | | |
|
|
| 19. | Angular speed can measure: a. | the rate at which an object moves in a straight
line. | b. | the rate at which an object revolves around an external
axis. | c. | the rate at which an object rotates around an internal
axis | d. | both the rate of
rotating and revolving. | | |
|
|
| 20. | Mao
watches a merry-go-round as it turns 27 times in 3 minutes. The angular speed of the merry-go-round
is ____ rpm.
|
|
| 21. | Three
students are seated on a merry-go-round. Randy is seated closest to the center, Toby is seated near
the outer edge, and Rasheed is seated between them. As the merry-go round turns: a. | Randy has the
greatest linear speed but the lowest angular speed. | b. | Toby has the
highest linear speed and the same angular speed as the others. | c. | Rasheed has the
same linear speed as the others but the highest angular speed. | d. | All three
students have the same linear and angular speed. | | |
|
|
| 22. | Anika
twirls a ball on a string which is 3.0 meters long. If the ball makes 2 revolutions per second, the
linear speed of the ball is about ____ m/sec.
|
|
| 23. | Spiderman swings on the end of a web that is 20 meters long in an arc of 45 degrees to
get from one building to another. The trip takes him 5.0 seconds. Spiderman travels from building to
building at a linear speed of about ____ m/sec.
|
|
| 24. | A
record rotating a 33 RPM’s has an angular speed of: a. | 33º/min. | b. | 55º/sec. | c. | 198º/sec. | d. | 55º/min. | | |
|
|
| 25. | Erica
pedals her bicycle from home to a local store 2.5 miles (13,200 feet) away. The wheels on
Erica’s bicycle have a diameter of 27 inches. The number of revolutions made by the wheels of
her bicycle on this ride is about: a. | 1,100. | b. | 1,900. | c. | 13,000. | d. | 22,000. | | |
|
|
| 26. | The
speedometer on a bicycle registers speed by converting angular speed of the bicycle’s wheel to
linear speed. What is the approximate speed that would be indicated by the speedometer of a bicycle
wheel with a diameter of 0.70 meters rotating at a rate of 3.0 rotations per second? a. | 2.2
m/sec | b. | 4.3 m/sec | c. | 6.6
m/sec. | d. | 21 m/sec. | | |
|
|
| 27. | Any
force that causes an object to move in a circle is called ____ force. a. | gravitational | b. | centripetal | c. | linear | d. | frictional | | |
|
|
| 28. | The
source of the centripetal force that allows a race car to go around a corner is: a. | gravity. | b. | friction. | c. | inertia. | d. | momentum. | | |
|
|
| 29. | The
weight of an automobile depends upon all of the following factors EXCEPT the: a. | speed of the
automobile on the road. | b. | mass of the earth. | c. | mass of the
automobile. | d. | distance of the automobile from the Earth’s
center. | | |
|
|
| 30. | The
path followed by one object as it revolves around another is called its: a. | trajectory. | b. | orbit. | c. | satellite. | d. | center of mass. | | |
|
|
| 31. | Factors that affect the amount of centripetal force on an object moving in a circle
include all of the following EXCEPT: a. | speed of the object. | b. | radius of
revolution. | c. | mass of the object. | d. | direction of
motion (clockwise or counterclockwise). | | |
|
|
| 32. | All
of the following represent objects that are being accelerated EXCEPT a: a. | car moving
around a corner at a constant speed of 30 miles per hour. | b. | competitor in a
track meet increasing speed at the finish line to pass another runner. | c. | bird flying in a
straight line from one tree to another at high speed. | d. | jet airliner
banking into a turn as it slows to prepare for a landing. | | |
|
|
| 33. | According to the diagram, the direction of the centripetal force on the airplane is
directed toward:
|
|
| 34. | If
you climb a hill, you are farther from the center of Earth. Due to your new location, your weight
will: a. | decrease by a
tiny amount. | b. | decrease by a large amount. | c. | increase by a
tiny amount. | d. | increase by a large amount. | | |
|
|
| 35. | If
the radius of the curve around which a car is driven is increased, the following can be said about
the centripetal force required to cause the car to go around the corner at constant
speed: a. | The centripetal
force increases. | b. | The centripetal force decreases. | c. | The centripetal
force remains the same. | d. | There is insufficient information to make a determination about
the centripetal force. | | |
|
|
| 36. | A
ball is being twirled on the end of a string as pictured in the diagram:
If the string is released when the ball reaches point
P, the inertia of the ball will cause it to move in the direction of:
|
|
| 37. | The
centripetal force on a 20-kilogram object revolving on the end of a 10-meter long cord is 20 newtons.
If the linear speed of the object is doubled, the centripetal force required to keep it moving in a
circle of the same radius is ____ newtons.
|
|
| 38. | Examples of centripetal force include all of the following EXCEPT: a. | gravity of the
sun acting to keep Earth in orbit. | b. | the door of a car pushing on a passenger as the car rounds a
corner. | c. | the friction between a dragster and the track as the car
accelerates down the drag strip. | d. | the force of the air pushing on the wings of a plane as it
makes a turn. | | |
|
|
| 39. | The
force required to keep an object moving in a circle of the same radius while its mass is doubled and
its speed is reduced to half would be: a. | the same. | b. | doubled. | c. | halved. | d. | quadrupled. | | |
|
|
| 40. | If
the distance between two objects is doubled while the masses of both objects are doubled, the
gravitational force between them is: a. | halved. | b. | the
same. | c. | doubled. | d. | quadrupled. | | |
|
|
| 41. | The
point around which an object naturally spins is called its: a. | trajectory. | b. | orbit. | c. | satellite. | d. | center of mass. | | |
|
|
| 42. | A
sport utility vehicle will roll over if the: a. | center of gravity is raised above its area of
support. | b. | area of support includes the center of
mass. | c. | center of mass passes outside of the area of
support. | d. | torque caused by the object’s weight is
balanced. | | |
|
|
| 43. | The
center of mass of an object: a. | is always the same as the center of
gravity. | b. | does not exist if the object has an irregular
shape. | c. | is sometimes outside of the object. | d. | is always
somewhere inside the object. | | |
|
|
| 44. |
This toy bird balances on the tip of the finger
because: a. | the torque
caused by the force of the bird’s weight is greater at the beak than the
tail. | b. | the center of gravity is in line with the
finger. | c. | the bird’s weight is outside its area of
support. | d. | It can’t possibly balance like that. It must be glued onto
the finger. | | |
|
Completion
Complete each sentence or
statement.
|
| | 45. | A
fluid such as oil used to reduce friction is called a ____________________.
|
| | 46. | The
rotational equivalent of force that causes objects to rotate about a point is called
____________________.
|
| | 47. | A
see-saw that is balanced has a net torque of zero applied to it. It is said to be in
_________________________ (two words).
|
| | 48. | The
size of a scalar or vector quantity may be called its ____________________.
|
| | 49. | The
sum of two or more vectors is called the ____________________.
|
| | 50. | When
the net force that acts on a body is zero, the forces are balanced. This represents a condition
called ____________________.
|
| | 51. | A
diagram that uses vectors to show all of the forces acting on an object is known as a
____________________ diagram.
|
| | 52. | The
path that a projectile follows after being fired is called its ____________________.
|
| | 53. | The
vertical and horizontal components of a projectiles motion are ____________________ of one
another.
|
| | 54. | If a
ball, fired as a projectile, travels 30 meters when it leaves the ground at a 20º
angle, it will travel the same distance when fired at an angle of ____________________
degrees.
|
| | 55. | The
rate of revolving or rotating is described as spins per unit of time, called ____________________
speed.
|
| | 56. | A
vertical line around which an object may rotate or revolve is called its internal or external
____________________.
|
| | 57. | Any
force which causes an object to move in a circle is called a ____________________
force.
|
| | 58. | The
name commonly given to the centripetal force acting between the sun and Earth that keeps Earth in
orbit around the sun is called the force of ____________________.
|
| | 59. | Scientists call an object that orbits another object a
____________________.
|
| | 60. | The
average position of all the particles that make up the mass of an object is called its
____________________ (three words).
|
Short Answer
|
| | 61. | List
three ways to reduce friction.
|
| | 62. | Identify each of the following as a scalar or vector
quantity:
a. speed
b.
mass
c. velocity
d. length
e.
temperature
f. time
g.
weight
|
| | 63. | Name
three factors that can affect the range of a projectile.
|
| | 64. | Of
the following flying objects, list those that are projectiles:
a. A jet plane
just after take-off
b. A baseball hit by a star baseball player
c. A free-throw
after being released by a basketball player
d. A rock thrown
from a bridge into a river below
e. A bird flying between
trees
f. A young woman diving from the starting block into a swimming
pool
|
| | 65. | Projectile motion may be separated into two components, vertical and horizontal. In
addition to the difference in their directions, state another difference between these motion
vectors.
|
| | 66. | Malik
and Destiny are seated on a moving merry-go-round. Malik is closer to the center than Destiny.
Briefly describe the similarity or difference in their speeds in terms of angular speed and linear
speed.
|
| | 67. | List
examples of three objects that are revolving and three that are rotating.
|
| | 68. | If
the distance between two objects is doubled, what happens to the force of gravity between
them?
|
| | 69. | Briefly describe how you might lose weight simply by changing your
location.
|
| | 70. | Imagine you are twirling a ball tied to the end of a string in a counterclockwise
direction above your head. Draw a circle to represent the path of the ball. On that circle draw
arrows to represent the following:
(a) The direction of the speed of the ball; label it
V.
(b) The direction of the acceleration of the ball; label it
A.
(c) The direction of the centripetal force on the ball; label it
F.
|
Problem
|
| | 71. | Using
a scale of 1 centimeter = 1 newton, represent the following displacement
vectors:
(a) 5 newtons west
(b) 3 newtons,
270º
(c) 4 newtons, 0º
|
| | 72. | Alexis pulls with 3 newtons on a toy doll toward east. Brianna pulls on the same toy
toward south with 2 newtons. Calculate the magnitude of the resultant force on the toy.
|
| | 73. | A
scale of 1 centimeter = 1 newton was used to draw the vector represented. Using a centimeter ruler,
draw and identify the magnitude of the horizontal and vertical components of the 4.5-newton force
illustrated in the vector drawing below:
|
| | 74. | A can
of soda sits motionless on a table. Make a free-body diagram of the forces acting upon the
can.
|
| | 75. | When
a 20-newton weight is hung on a spring, it stretches 16 centimeters. How far does the spring stretch
if a 5.0-newton weight is hung from the spring?
|
| | 76. | The
diagram below represents a lever with three forces applied to it at different positions. A
four-newton, clockwise force is applied one meter from the right end of the lever. A ten-newton,
clockwise force is applied 5 meters to the left of the four newton force.
For the lever to be in equilibrium, what is the size
of the counterclockwise force applied four meters from the right end of the lever?
|
| | 77. | A
bowling ball rolls off a horizontal loading platform 2.0 meters high with a speed of 3.0 m/sec. How
long will it take to hit the ground?
|
| | 78. | A
quarterback throws a football, giving it a vertical velocity of 9.2 meters per second and a
horizontal velocity of 25.4 meters per second. Calculate the vertical and horizontal components of
the football’s velocity after 1.00 second.
|
| | 79. | A
rocket is fired into the air with vertical velocity of 58.8 meters per second.and a horizontal
velocity of 21.3 meters per second. Assuming the rocket is in free-fall, calculate the range of the
rocket.
|
| | 80. | Calculate the angular speed of a bicycle wheel that makes 240 rotations in 6
minutes.
|
| | 81. | Calculate the number of degrees a wheel has rotated when it has gone twice
around.
|
| | 82. | A
barrel with a circumference of 2.0 meters rolls 12 meters in 3.0 seconds. Calculate the angular speed
of the barrel.
|
| | 83. | Use
the information below to calculate the weight of a 2,000-kilogram car on Earth’s
surface.
G, the universal gravitational constant = 6.67 ´
10-11Nm2/kg2
Mass of Earth =
5.97 ´ 1024 kg
Radius of Earth
= 6.38 ´ 106 m
|
| | 84. | The
centripetal force needed to cause a 2,000-kilogram truck to safely round a curve at 15 meters per
second is 13,000 newtons. If a 2,000-kilogram load is added to the truck but the driver cautiously
slows to 7.5 meters per second in rounding the curve, how much force is required to safely negotiate
the curve?
|
| | 85. | Two
objects are placed near one another. The mass of one object is doubled while the distance between the
objects is tripled. What net change takes place in the force of gravity between the
objects?
|