Download fall04-term2-exercise

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Modified Newtonian dynamics wikipedia , lookup

Classical mechanics wikipedia , lookup

N-body problem wikipedia , lookup

Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup

Momentum wikipedia , lookup

Force wikipedia , lookup

Specific impulse wikipedia , lookup

Faster-than-light wikipedia , lookup

Atomic theory wikipedia , lookup

Newton's theorem of revolving orbits wikipedia , lookup

Newton's laws of motion wikipedia , lookup

Mass in special relativity wikipedia , lookup

Hunting oscillation wikipedia , lookup

Electromagnetic mass wikipedia , lookup

Vibration wikipedia , lookup

Seismometer wikipedia , lookup

Work (physics) wikipedia , lookup

Inertia wikipedia , lookup

Centripetal force wikipedia , lookup

Center of mass wikipedia , lookup

Classical central-force problem wikipedia , lookup

Relativistic mechanics wikipedia , lookup

Transcript
Phys1443-003, Fall04,Term 2 Exercise Problems
Page 1
1.
Two objects attract each other gravitationally with a force of 2.5 ð 10-10
N when they are 0.25 m apart. It their total mass is 4.0 kg, their individual
masses are:
a. 1.5 and 2.5 kg
b. each 2 kg
c. 0.5 and 3.5 kg
d. need more information
2.
Two objects have mass m and 2m respectively and are separated by a distance
d. At what distance from the lighter object along the line joining the two
objects would the net gravitational force on a third object be zero?
a. 0.25 d
b. 0.41 d
c.0.5 d
d. 0.81 d
3.
Three 5 kg masses sit at the vertices of an equilateral triangle of side 1
m. The magnitude of the gravitational force on any of the masses due to the
other two is
a. 1.2 ð 10-11 N
b. 2.5 ð 10-10 N
c. 2.9 ð 10-9 N
d. 3.4 ð 10-8 N
4.
An object of mass 5 kg weighs 49 N at the surface of the Earth. At an altitude
equal to twice the Earth's radius its weight is
a. 12.3 N
b. 24.5 N
c.49 N
d. 98 N
5.
The gravitational acceleration g at the surface of two hypothetical planets
has the same value, but planet #1 has twice the radius of planet #2. The ratio
of the mass of planet #1 to that of #2 is
a. 2:1
b. 1:2
c.4:1
d. 1:4
6.
The period of a satellite orbiting the Earth 2000 km above the surface is
a. 3.5 ð 103 s
b. 7.6 ð 103 s
3
c. 8.5 ð 10 s
d. 9.0 ð 103 s
7.
A satellite orbits the Earth with a speed of 4500 m/s. Its period is
a. 1.5 ð 103 s
b. 2.1 ð 104 s
c. 2.7 ð 104 s
d. 3.5 ð 104 s
8.
Which of the following statements is true regarding satellites in circular
orbits about a planet?
a. The period depends on the mass of the satellite
b. The period is independent of the radius of the orbit
c. The speed of the satellite can change as it maintains its circular orbit
d. The period increases with increasing orbital radius
9.
A satellite of mass 5000 kg orbits the Earth (mass = 6.0 ð 1024 kg) and has
a period of 6000 s. The magnitude of the Earth's gravitational force on the
satellite is
a. 7.9 ð 10-3 N
b. 7.9 ð 10-2 N
c. 7.9 N
d. 7.9 ð 103 N
10. The period of a satellite orbiting just above the Earth's surface is
a. 2500 s
b. 5040 s
c. 7500 s
d. 86,400 s
1
Phys1443-003, Fall04,Term 2 Exercise Problems
11. Two satellites are in circular orbits about the Earth, with satellite 2 in
an orbit of larger radius than satellite 1. Which satellite has the longer
period?
a. satellite 1
b. satellite 2
c. need to know the masses of the satellites
12. Satellite #1 has three times the mass of satellite #2. Both are in circular
orbits of the same radius about Earth. The ratio of the speed of satellite
#1 to the speed of satellite #2 is
a. 3:1
b. 1:3
c.2:1
d. 1:1
13. The speed of Halley's comet at its point of closest approach to the Sun is
a. the same as its speed throughout its orbit
b. greater than its value at any other point in its orbit
c. less than its value at any other point in its orbit
14. Four equal masses are located at the corners of a square. The direction of
the gravitational field at the midpoint of the lower side of the square is
a. up
b. down
c.left
d. right
15. The gravitational field at the center of the Earth has magnitude
a. zero N/kg
b. 6.67 ð 10-11 N/kg
c. 9.8 N/kg
d. infinity
16. If the inertial mass and the gravitational mass were not equal, which of the
following principles would change?
a. the inverse-square law of gravitation
b. Kepler's Third Law
c. Newton's Second Law
A satellite of mass 5000 kg orbits the Earth (mass = 6.0 ð 1024 kg) and has a
period of 6000 s.
17. In the above problem the altitude of the satellite above the Earth's surface
is
a. 7 ð 103 m
b. 7 ð 105 m
c.4 ð 106 m
d. 5 ð 108 m
Two objects attract each other gravitationally with a force of 2.5 ð 10-10 N when
they are 0.25 m apart.
18. In the above problem if the two objects experience no forces other than their
mutual gravitational attraction then their resulting accelerations are
a. equal
b. different
Two satellites are in circular orbits about the Earth, with satellite 2 in an
orbit of larger radius than satellite 1.
19. In the above problem which satellite has the larger speed?
a. satellite 1
b. satellite 2
c. need to know the masses of the satellites
The period of a satellite orbiting just above the Earth's surface is 5040 s.
20. The mass of the satellite in the above problem is
2
Phys1443-003, Fall04,Term 2 Exercise Problems
a. 5000 kg
b. 9.8 kg
5
c. 2.5 ð 10 kg
d. need more information
21. The speed of the satellite in the above problem is
a. 3070 m/s
b. 7780 m/s
c.7900 m/s
d. 8500 m/s
Three 5 kg masses sit at the vertices of an equilateral triangle of side 1 m.
22. In
a.
b.
c.
the above example the force points
away from the center of the triangle
toward the center of the triangle
along a line joining two of the masses
Four equal masses are located at the corners of a square.
23. In the above problem if each mass is 1 kg and the square has side 0.5 m the
strength of the gravitational field at the midpoint of a side is
a. 1.6 ð 10-9 N/kg
b. 2.5 ð 10-9 N/kg
-9
c. 3.8 ð 10
N/kg
d. 3.8 ð 10-10 N/kg
24. If you lift a box of mass 5 kg straight up at constant speed through a
displacement of 1 m, the total work done on the box is
a. zero J
b. 49 J
c.-49 J
d. 25 J
25. The angle between a force F and a displacement d is 125ø. The work done by
the force is
a. zero
b. positive
c. negative
d. the sign depends on the magnitudes of F and d.
26. A particle moves in uniform circular motion. The work done on it by the
centripetal force is
a. zero
b. positive
c. negative
27. A box of mass 5 kg is accelerated by a force across the floor at a rate of
2 m/s2 for 10 s. The work done by the force is
a. 50 J
b. 100 J
c.1000 J
d. 1500 J
28. A box of mass 10 kg slides down a plane inclined at an angle of 30ø with the
horizontal. The coefficient of kinetic friction between the box and the
incline is 0.2. The length of the incline is 5 m. The work done by friction
is
a. -9 J
b. -98 J
c.85 J
d. -85 J
29. The dot product of vectors A and B equals 4. If A has magnitude 2 and B has
magnitude 1.5 then the angle between the two vectors is
a. 40ø
b. 90ø
c. 135ø
d.the given information is inconsistent
30. Vectors A and B have components (1.5, 2.3) and (3.1, 4.5) respectively. Their
dot product is
a. 5.7
b. 15
c.-15
d. 11.4
31. A force F = 3i + 2j - 4k acts on an object moving it from a position
i + 5j - 4k to a position 3i - 2j + 8k. The work done by F is
a. 2
b. 56
c.-56
d. 48
3
Phys1443-003, Fall04,Term 2 Exercise Problems
4
Phys1443-003, Fall04,Term 2 Exercise Problems
32. If
a.
b.
c.
d.
two vectors satisfy A ú B = -AB then
they are parallel to each other
they are antiparallel to each other
they are perpendicular to each other
they make an angle of 45ø with each other
33. A spring with k = 50 N/m hangs vertically next to ruler. The end of the spring
is next to the 10 cm mark on the ruler. If a 2.5 kg mass is now attached to
the end of the spring, the end will line up with
a. the 10 cm mark
b.the 39 cm mark
c. the 49 cm mark
d. the 59 cm mark
34. The work done by a force F = k³x³ on an object moving from x = -2 to
x = 2 is
a. zero
b. 2 k
c. 4 k
d. 8 k
35. A particle moves from x = 2 to x = 3.5 subject to a force F = 5x + 7x2 which
points in the y direction. The work done by F is
a. zero
b. 102
c. -102
d. 150
36. A box of mass 10 kg slides down a plane inclined at an angle of 30ø with the
horizontal. The coefficient of kinetic friction between the box and the
incline is 0.2. The length of the incline is 5 m. If the box is released from
rest at the top of the incline, its speed at the bottom is
a. 5.7 m/s
b. 7.0 m/s
c. 9.0 m/s
d. 12.3 m/s
37. A platform is supported by a spring with k = 1.0 kN/m. The spring is compressed
1 cm due to the weight of the platform. A box of mass 20 kg is then placed on
the platform and the system begins to oscillate up and down. Calculate how far
the platform descends below its initial position.
a. 15 cm
b. 16 cm
c. 17 cm
d. 25 cm
38. A box is given a push across a table so that its initial speed is vo. The
box travels a distance d and is brought to rest by friction. If instead the
box is given an initial speed of 2vo, the box will travel a distance
a. d
b. 2d
c.3d
d. 4d
39. An object of mass 10 kg is released from the top of a building 100 m high.
If the average force of air resistance experienced by the object is 15 N,
its speed when it hits the ground is
a. 22 m/s
b. 30 m/s
c. 41 m/s
d. 52 m/s
40. A box is given an initial velocity of 5 m/s. It slides across a rough surface
coming to rest in 2 m. The coefficient of kinetic friction is
a. 0.2
b. 0.4
c. 0.6
d. 0.7
41. A spring attached to 2 kg mass is compressed 10 cm and released from rest.
When the spring is compressed 5 cm, the mass is moving at 1.5 m/s. The spring
constant is
a. 450 N/m
b. 600 N/m
c. 750 N/m
d. 1000 N/m
42. A block of mass 10 kg is attached to a spring with spring constant 1000 N/m.
The spring is compressed 2 cm and released from rest. The speed of the block
as it passes through the equilibrium position of the spring is
5
Phys1443-003, Fall04,Term 2 Exercise Problems
a. 0.2 m/s
b. 0.4 m/s
c. 0.6 m/s
d. 0.8 m/s
43. A block of mass 5 kg is subject to a force F = 3x + 5x2 (in N). The block
is initially at rest at x = 1. Its speed when it has moved to
x = 5 is
a. 9.8 m/s
b. 19.6 m/s
c. 97 m/s
d. 105 m/s
44. A block of mass 10 kg moves on a frictionless table at 2 m/s and strikes a
spring attached to a wall. After the collision the spring is compressed to
a maximum distance of 0.9 m. The spring constant of the spring is
a. 100 N/m
b. 74 N/m
c. 49 N/m
d. need more information
45. A block of mass 1 kg is placed against a compressed spring of constant 500
N/m at the bottom of frictionless plane inclined at 30ø. When the spring is
released the block travels 1.5 m up the plane, losing contact with the spring.
The spring was initially compressed by a distance of
a. 10 cm
b. 13 cm
c. 15 cm
d. 17 cm
46. How much work is done in accelerating an electron (mass = 9.1 ð 10-31 kg)
from 0.5c to 0.9c?
a. 9.3 ð 10-31 J
b. 9.3 ð 10-14 J
c. 2.3 ð 10-14 J
d. 1.5 ð 10-14 J
Vectors A and B have components (1.5, 2.3) and (3.1, 4.5) respectively.
47. The angle between the vectors in the above problem is
a. 15ø
b. 29ø
c. 35ø
d. not enough information given
A box is given an initial velocity of 5 m/s. It slides across a rough surface
coming to rest in 2 m.
48. The mass of the box in the above problem is
a. 5 kg
b. 10 kg
d. not enough information provided
c. 25 kg
A block of mass 10 kg moves on a frictionless table at 2 m/s and strikes a spring
attached to a wall. After the collision the spring is compressed to a maximum
distance of 0.9 m.
49. In the above problem what is the speed of the block when the spring is
compressed 0.5 m?
a. 1.2 m/s
b. 1.7 m/s
c. 2.3 m/s
d. need more information
A block of mass 1 kg is placed against a compressed spring of constant 500 N/m
at the bottom of frictionless plane inclined at 30ø. When the spring is released
the block travels 1.5 m up the plane, losing contact with the spring.
50. In the above problem what is the speed of the block when it has traveled 0.9
m up the plane?
a. 1.7 m/s
b. 3.4 m/s
c. 4.1 m/s
d. 5.2 m/s
6
Phys1443-003, Fall04,Term 2 Exercise Problems
A box of mass 10 kg slides down a plane inclined at an angle of 30ø with the
horizontal. The coefficient of kinetic friction between the box and the incline
is 0.2. The length of the incline is 5 m.
51. The work done by the normal force in the above problem is
a. zero
b. 49 J
c. 123 J
d. 250
52. For the potential energy function U(x,y) = 3xy + 5x2 + 6y3, the force is given
by
a. F = 5x2i + 6y3j
b. F = 3xyi + 3xyj
c. F = (-3y - 10x)i + (-3x - 18y2)j
d.F = (3y + 10x)i + (-3x - 18y2)j
53. A spring is compressed a distance x and used to vertically launch a mass m
placed against its end. The mass reaches a height h. If the spring is instead
compressed a distance 2x, the height reached by the mass will be
a. h
b. 2h
c. 3h
d. 4h
54. A 1.5 kg mass rests atop a spring with spring constant 500 N/m. The spring
is compressed a distance 25 cm and released. The ball will ascend to a height
a. 0.5 m
b. 0.6 m
c. 0.8 m
d. 1.0 m
55. A block of mass 5 kg starts from rest at the top of a ramp which is 5 m high.
It descends to the bottom of the ramp and then rises to the top of a second
ramp which is 2.5 m high. The speed of the block at the top of the second
ramp is
a. 3.5 m/s
b. 7 m/s
c. 14 m/s
d.21 m/s
56. A toy car of mass 1.5 kg traveling on a level surface approaches a
loop-the-loop with radius 1.5 m. The minimum speed of the car required to
traverse the loop-the-loop is
a. 1. 5 m/s
b. 3.8 m/s
c. 4.6 m/s
d. 12.3 m/s
57. Three balls start at the same vertical position but follow different
frictionless paths as they descend a height h. Which of the following
statements is true?
a. The balls all reach the lower level at the same time.
b. The balls all reach the lower level with the same speed but at possibly
different times.
c. The ball that takes the longer path reaches the bottom with the lowest
velocity
d. The balls all reach the lower level with the same speed and at the same
time.
58. A roller coaster car starts from rest and descends 40 m before rising 20 m
to the top of a hill. The passenger of mass 75 kg at the top of the hill feels
a normal force of 368 N. The radius of curvature of the hill is
a. 10 m
b. 20 m
c. 30 m
d. 40 m
59. A small block falls from the rim of a bowl down towards the bottom, 15 cm
below. The maximum speed of the block neglecting friction is
a. 1.3 m/s
b. 1.5 m/s
c. 1.7 m/s
d. need to know the mass of the block
7
Phys1443-003, Fall04,Term 2 Exercise Problems
60. A mass of 2 kg is placed on an inclined plane (making an angle of 30ø with
the horizontal) and connected to a spring fastened at the top of the plane.
The spring has spring constant 50 N/m. The mass is released from rest with
the spring initially unstretched. The block moves a distance 25 cm before
coming to rest. The coefficient of kinetic friction between the block and
the plane is
a. 0.1
b. 0.2
c. 0.3
d. 0.4
61. A 5 kg block slides on a rough horizontal surface with speed 2.0 m/s. It makes
contact with a spring and momentarily stops when the spring is compressed
5 cm. The work done by friction from the moment the block contacts the spring
until it momentarily stops is -2.0 J. The spring constant of the spring is
a. 2000 N/m
b. 4000 N/m
c. 6400 N/m
d. 9600 N/m
62. An object is projected vertically upward from a planet of radius R with a
velocity equal to one half the escape velocity. The maximum altitude attained
by the object is
a. 0.3 R
b.0.5 R
c. 1.3
d. 1.5 R
63. A person ascends a flight of stairs in 20 s. The person weighs 500 N and the
vertical height of the stairs is 9 m. The person's power output is
a. 150 W
b. 225 W
c. 325 W
d. 450 W
64. An object moves with a potential energy given by U(x) = 2x2. If the particle's
energy is 2 then turning points of the motion are
a. 0 and infinity
b. 1 and -1
c. 1 and infinity d.-1 and infinity
65. The potential energy of a particle is given by U = x3 exp (-x2). The point
of stable equilibrium is given by
a. x = 0
b. x = 1.2
c. x = 2.4
d. there is no point of stable equilibrium
A 5 kg block slides on a rough horizontal surface with speed 2.0 m/s. It makes
contact with a spring and momentarily stops when the spring is compressed 5 cm.
The work done by friction from the moment the block contacts the spring until
it momentarily stops is -2.0 J.
66. In the above problem the coefficient of kinetic friction is
a. 0.3
b. 0.5
c. 0.6
d. 0.8
67. In the above problem when the spring pushes the block back the block's
velocity when it loses contact with the spring is
a. 1.5 m/s
b. 2.0 m/s
c. 2.5 m/s
d. 3.5 m/s
A roller coaster car starts from rest and descends 40 m before rising 20 m to
the top of a hill. The passenger of mass 75 kg at the top of the hill feels a
normal force of 368 N.
68. Suppose the roller coaster in the above problem starts with a speed of 5 m/s.
Its speed at the top of the next hill is
a. 16 m/s
b. 21 m/s
c. 25 m/s
d. 30 m/s
An object moves with a potential energy given by U(x) = 2x2.
69. The maximum kinetic energy of the object in the above problem is
a. 1.125
b. 0
c. 2
d.not enough information
8
Phys1443-003, Fall04,Term 2 Exercise Problems
70. The equilibrium position of the object in the above problem is located at
a. x = 0
b. x = -0.5
c. x = -1.25
d. x = -2
71. The equilibrium position located in the above problem is
a. stable
b. unstable
c. not enough information
72. A particle moving in the x direction feels a force of F(t) = 3t + 4 Newtons
where t is in seconds. What is the momentum change between t = 0 and t = 2.
s?
a. -2. N-s
b. 0. N-s
c. 12. N-s
d. 14. N-s
73. Two railroad cars collide on a level track and lock together. The collision:
a. was elastic
b. reduced momentum
c. was inelastic
d. conserved kinetic energy
74. Assume a rocket is far enough in space that the acceleration due to gravity
is negligible. If the mass ratio, initial mass/final mass, changes from 10
to 20 for the same exhaust velocity, by what factor does the increase of
velocity change?
a. 2.0
b. 0.50
c. 0.69
d. 1.3
75. Which of the following units may be used to describe momentum?
a. N-s
b. N/s
c. N-m
d. N/m
76. A 200. Megagram rocket on the launchpad consists of 190. Megagrams of fuel
which is burned at the rate of 2.0 Megagrams/second with an exhaust speed
of 3.0 km/s. What thrust is produced by the engines?
a. 2.0 ð 106 N
b. 4.0 ð 106 N
c. 6.0 ð 106 N
d.8.0 ð 106 N
77. The pitcher throws a 44. m/s fastball. The bat reverses the ball's velocity
and it leaves the bat at 56. m/s. What was the average force on the 0.145
kg baseball during the contact time of 15. ms?
a. 0.43 KN
b. 0.54 KN
c. 0.97 KN
d. 1.45 KN
78. As the bullet enters the wood block of a ballistic pendulum, which is/are
conserved?
a. kinetic energy and momentum
b.kinetic energy but not momentum
c. momentum but not kinetic energy
d.neither kinetic energy nor momentum
79. A particle moves with momentum p. Which of the following describe its kinetic
energy?
a. p/m
b. 1/2 mp2
c. p2/2m
d. 1/2 p/m
80. A 3500. kg parked car, with brakes off and free to move, is bumped from the
rear by a 2000. kg car moving 4.0m/s and they lock bumpers. What percentage
kinetic energy is lost in the collision?
a. 36
b. 48
c. 64
d. 77
81. In an inelastic collision, the ______ is less after the collision than before.
a. momentum
b. total energy
c. kinetic energy
82. Three masses are positioned thus: 2.0 kg at (0,0), 3.0 kg at (10,20), 5.0
kg at (-10,30). Where is the cm?
9
Phys1443-003, Fall04,Term 2 Exercise Problems
a. (-2, 21)
b.(2, 21)
c.(-2.5, 26)
d.(2.5, 26)
83. Consider two astronauts initially at rest "floating" next to each other in
space. The 80. kg astronaut pushes the 100. kg astronaut. How far apart are they
when the heavier astronaut has moved 10. meters?
a. 8.0 m
b. 18. m
c. 12.5 m
d.22.5 m
84. Suppose you were to throw a firecracker straight up and it exploded into 2
pieces when it reached its maximum height of 6.5 meters. Both pieces are
initially flung horizontally but then fall to the ground. The 37. gram piece
hits the ground 1.9 meters to your left. How far to your right does the 63.
gram piece hit the ground?
a. 0.93 m
b.1.1 m
c. 1.8 m
d. 3.2 m
85. How long would a force have to act starting from zero and linearly increasing
with time such that 20. kg-m/s is the momentum change produced (dF/dt = 5.0
N/s)?
a. 2.8 s
b. 4.0 s
c. 8.0 s
d. 9.2 s
86. What is the angular speed of rotation of the earth?
a. 6.94 ð 10-4 rpm
b. 4.36 ð 10-3 radian/s
c. 7.27 ð 10-5 rpm
d. 8.34 ð 10-4 degree/s
87. A Ferris Wheel has a diameter of 25.0 meters. How far does a person on the
rim travel when the wheel rotates 120. degrees?
a. 8.33 m
b. 3.00 ð 103 m c. 26.2 m
d. 52.4 m
88. A 30.cm diameter wheel rolls without slipping at 120. rpm. The point of
contact with the ground has an instantaneous speed of:
a. 5.2 mm/s
b. 1.04 cm/s
c. 2.6 m/s
d. zero
89. Which of the following is not a vector?
a. angular velocity
b. angular acceleration
c. angle
d. torque
90. A spinning ice skater draws her arms in closer to her body. As she does so
the:
a. angular speed decreases
b. angular momentum increases
c. torque on the skater decreases
d. angular momentum is constant
91. An
in
a.
c.
old 33 1/3 rpm record player starts from rest and reaches operating speed
2.0 seconds. Through what angle did it turn in those 2.0 s?
0.56 radian
b. 0.56 revolution
3.5 radians
d. 3.5 revolutions
92. At a point 1.2 m out from the hinge, 14. Newtons is exerted at an angle of
27.ø to the radius in a plane which is perpendicular to the door. What
magnitude torque is exerted?
a. 7.6 N-m
b. 9.7 N-m
c. 15. N-m
d. 17. N-m
93. Estimate the rotational kinetic energy of the rotating earth (assume earth
is a uniform sphere of mass 6.0 ð 1024 kg and radius 6.4 ð 103 km).
a. 2.6 ð 1025 J
b. 2.6 ð 1027 J
c. 2.6 ð 1029 J
d. 2.6 ð 1031 J
10
Phys1443-003, Fall04,Term 2 Exercise Problems
94. What is the ratio of angular momentum of earth orbiting the sun and the angular
momentum of the moon orbiting the earth? earth/moon mass = 81.;
earth-sun/earth-moon distance = 391.; moon period = 27.3 days
a. 2.4 ð 103
b. 9.2 ð 105
c. 1.7 ð 108
d. 6.1
95. A 200. hp automobile engine delivers what torque at 3000. rpm?
a. 0.637 N-m
b. 77.3 N-m
c. 475. N-m
d. 950. N-m
96. What is the ratio of the kinetic energy per unit mass of the earth orbiting
the sun and the kinetic energy per unit mass of the moon orbiting the earth?
earth/moon mass = 81.; earth-sun/earth-moon distance = 391.; moon period =
27.3 days
a. 85.
b. 8.5 ð 102
c. 8.5 ð 103
d. 8.5 ð 104
97. A yoyo is placed so it can roll on the floor without slipping and its string
(wound around its central small radius peg) is pulled horizontally such that
the string is below the center of mass. Does the yoyo roll toward the person
pulling (thus shortening the string) or does it roll away from the person
pulling (thus lengthening the string)?
a. toward
b.away
98. A yoyo is placed so it can roll on the floor without slipping and its string
(wound around its central small radius peg) is pulled horizontally such that
the string is above the center of mass. Does the yoyo roll such that it
lengthens the string or does it roll such as to shorten the string?
a. lengthens
b. shortens
99. In the presence of frictional forces, the total mechanical energy always
decreases. True or false?
a. True
b. False
100. Two blocks of different masses are projected up a rough inclined plane with
the same initial speed. True or false: Both blocks reach the same height.
a. True
b. False
11
Phys1443-003, Fall04,Term 2 Exercise Problems
Answer keys! The answers have not been checked. So please use these with a grain of salt!!
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
a
b
c
a
c
b
c
d
c
b
b
d
b
a
a
b
b
b
a
d
c
b
d
a
c
a
c
d
d
b
c
b
d
c
a
a
b
d
c
c
b
a
a
c
d
b
b
d
b
b
a
c
d
12
Phys1443-003, Fall04,Term 2 Exercise Problems
54. d
55. b
56. b
57. b
58. b
59. c
60. b
61. c
62. a
63. b
64. b
65. b
66. d
67. a
68. b
69. c
70. a
71. a
72. d
73. c
74. d
75. a
76. c
77. c
78. c
79. c
80. c
81. c
82. a
83. d
84. b
85. a
86. a
87. c
88. d
89. c
90. d
91. d
92. a
93. c
94. b
95. c
96. b
97. a
98. a
99. True
100. False
13