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Physics 111 Final Exam - Version B(key)
Signature_____________________________
4 Digit ID___________
May 14, 2002
Name (Print) _____________________________
Section ______
Instructions:
 You may use both sides of two 8.5 x 11 sheets for formulas and reference information.
 Choose 30 of the 40 questions on the test. Each is worth 3 1/3 points.
 If you answer more than 30 questions, only the FIRST 30 will be counted.
 Answer all questions on the Scantron sheet. Be sure your name and section number are on both the
Scantron form and the question sheet. You may use backs of the question papers for extra space.
 Before you hand in your paper, place an X next to the question numbers you did NOT chose on both
the Scantron sheet and the test paper.
 For all problems, g = 9.80 m/s2.
 Make sure to bring your own calculator. Sharing of calculators is not permitted.
 Please turn off any cell phones, pagers, communication or entertainment devices, etc.
 Students are not to communicate with each other once the test has started.
1. One meter is equivalent to 3.281 ft. A cube with each edge 1.5 feet long has a volume of:
A) 10.5 m3
D) 9.6 x 10–2 m3
B) 0.21 m3
C) .2x102 m3
–2
3
E) 9.5 x 10 m
2. (FE) What angle does the force F make with the y-axis in the accompanying diagram?
The force is given by F = 7i + 3j + 8k.
A) 1100
D) 230
B) 740
E) 160
Y
x
C) 670
j
k
i
x
F
Z
x
3. A vector a of magnitude 6 and another vector b have a resultant of magnitude 12. The vector b
A) may have a magnitude of 20
B) cannot have a magnitude greater than 12
C) must be perpendicular to a
D) must have a magnitude of at least 6 but no more than 18
E) must be perpendicular to the resultant vector
4. A motorcycle starts from rest at a traffic light. It travels 100 meters in 5 seconds. The acceleration of the motorcycle
is:
A) 4.0 m/s2
B) 40.0 m/ s2
C) 20.0 m/s2
D) 8.0 m/s2
E) 80.0 m/s2
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5. A rifle that shoots bullets at 500 m/s is fired at a target on level ground. If the rifle is pointed 15 degrees above the
horizontal when it is fired, how far away horizontally from the target should the person shooting be to hit the target?
Neglect all air resistance and assume that g is the same everywhere.
A) 854 m
B) 1708 m
C) 3416 m
D) 6380 m
E) 12,760 m.
6. A car is traveling east at 72 km/h. It rounds a curve and 5 seconds later is traveling north at 72 km/h.
Suppose
that east is the positive x direction and north is the positive y direction as shown in the sketch. Find the average
acceleration of the car.
A) 4 m/s2 to the northwest
C) 14.4 m/s2 to the northeast
E) 14.4 m/s2 to the southeast
B) D) 4 m/s2 to the northeast
D) 14.4 m/s2 to the northwest
N
NW
NE
W
E
SW
SE
S
7. An object moving at constant velocity in an inertial (non-accelerated) frame of reference must:
A) have a net force acting on it
C) not have any force of gravity acting on it
E) have zero net force acting on it
B) eventually stop due to gravity
D) have no frictional force acting on it
8. In the sketch at right, assume that the pulley is massless and all surfaces are frictionless. What is the magnitude of
the acceleration of mass m1 in terms of m1, m2, and g?
A) m2g / (m1 + m2 )
D) m1g / (m2 - m1 )
B) m1g / (m1 + m2 )
E) (m1 + m2)g / m2
C) m2g / (m1 - m2)
m1
m2
9. For the arrangement shown in the sketch for problem 8 above, now assume that the coefficients of static and kinetic
friction between m1 and the table are s = .2 and k = .15. If m1 = 10 kg and m2 = 5 kg, find the magnitude of the
acceleration of mass m1.
A) 4.25 m/s2
B) 4.57 m/s2
C) 0.0 m/s2
D) 1.96 m/s2
E) 2.29 m/s2
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10. (FE) The block in the sketch is initially stationary. It may or may not slide down the ramp. What will the actual
frictional force be between the 80 kg block and the ramp (either static or kinetic)?. The coefficient of static friction is
0.20 and the coefficient of kinetic (sliding) friction is 0.15.
A) 60 N.
D) 90 N.
B) 80 N.
E) 180 N.
C) 120 N .
80 kg
400
11. A car is following a curve to the left at a constant speed of 25 m/s on a level road. The curve is a section of a circle
whose radius is 225 meters. A 75 kg passenger in the right front seat tends to slide to the right during the turn.
What net force must act on him/her to prevent the sliding?
A) 0 N.
B) 2.78 N.
C) 8.3 N.
D) 208 N.
E) 735 N.
12. A floating ice block is pushed through a displacement d = 30i - 24j (meters) along a straight embankment by
rushing water, which exerts a force F = 210i - 150j (Newtons) on the block. How much work does the force do on
the block during the displacement?
A) 9900 J.
B) 6300 J
C) 4500 J.
D) 3600 J.
E) 2700 J
13. A 50 kg block is pulled at a constant speed of 15.0 m/s across a horizontal floor by an applied force of 125 N
directed 53° above the horizontal. What is the rate at which the force does work on the block?
A) 75.2 Watts
D) 2037 Watts.
B) 1875 Watts
E) 5625 Watts
C) 1128 Watts
F
53o
50 kg
v
14. A conservative force F(x) acts on a 2.0 kg particle that is moving along the x axis. The potential energy U(x)
associated with F(x) is graphed in the figure. The mechanical energy = - 5 joules as shown. What is the particle's
speed at x = 10.0 meters? Which way does the force on it point?
A) v = 2.2 m/s, F to the left
B) v = 2.2 m/s, F to the right
C) v = 3.2 m/s, F to the left
D) v = 3.2 m/s, F to the right
E) v = 3.9 m/s, F to the right
Emech
15. A 1 kg basketball is dropped from the fifth floor of an apartment building (15 meters high) onto the sidewalk below.
The collision dissipates 50% of the energy as heat. How high does the ball bounce?
A) 10.6 meters
B) 15 meters
C) 7.5 meters
D) 5 meters
E) 3 meters
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16. The string in the figure is L = 100 cm long, has a ball of mass m attached to one end and is fixed at its other end.
The distance d to the fixed peg at point P is 70.0 cm. The ball is released from rest with the string horizontal as
shown. It will swing along the dashed arc. What is the ball's speed when it reaches its highest point after the string
catches on the peg (directly over point P)?
A) 4.42 m/s
B) 3.96 m/s
C) 3.92 m/s
D) 3.13 m/s
E) 2.80 m/s
17. A 75 kg skier skis down a 100 meter long slope making a 20o angle to the horizontal.
Ug = 0 The sliding friction force
between his skis and the hill is 100 N. If he starts from rest at the top, what is his speed at the bottom of the hill?
A) 14.2 m/s
B) 28.4 m/s
C) 20.1 m/s
D) 40.2 m/s
E) 25.9 m/s
Skier
100 m
18. (FE) An L-shaped piece, represented by the shaded area on the figure, is cut from a metal plate of uniform
thickness. The point that corresponds to the center of mass of the L-shaped piece is
A) 1
B) 2
C) 3
D) 4 E) 5
19. A man is sittng in the back of a canoe in still water. He then moves to the front of the canoe and sits down there.
Afterwards the canoe:
A) is rearward of its original position and moving forward
B) is rearward of its original position and moving backward
C) is rearward of its original position and not moving
D) is forward of its original position and moving forward
E) is forward of its original position and moving backward
20. A 2.0 kg. ball drops vertically onto a floor, hitting with a speed of 20 m/s. It rebounds with an initial speed of 10
m/s. The ball is in contact with the floor for 0.02 seconds as it receives the impulse. What is the magnitude of the
average force on the ball from the floor?
A) 1000 N.
B) 2000 N.
C) 3000 N.
D) 4000 N.
E) 5000 N.
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21. Two bodies, x and y, have equal kinetic energies. The mass of x is nine times that of y. The ratio of the momentum
of y to that of x is:
A) 1:9
B) 1:3
C) 1:1
D) 3:1
E) 9:1
22. A projectile in flight explodes into several fragments. The total momentum of the fragments immediately after this
explosion:
A) is the same as the momentum of the projectile immediately before the explosion
B) has been changed into kinetic energy of the fragments
C) is less than the momentum of the projectile immediately before the explosion
D) is more than the momentum of the projectile immediately before the explosion
E) has been changed into radiant energy
23. The angular speed in rad/s of the second hand of a watch is:
A) /1800
B) /60
C) /30
D) 2

E) 60
24. Four identical balls of mass M are connected by massless rods as shown in the picture. The distance from point B to
each ball is L meters. Find the rotational inertia IB about an axis through B perpendicular to the paper. Then find the
rotational inertia IA about an axis through point A, also perpendicular to the paper. The ratio IB/ IA is:
A) 4
B) 20
C) 1
D) 0.5 
E) 0.25
L
L
L
B
A
C
L
25. A 10 kilogram bicycle wheel is rotating at 60 rev/min. It is essentially a thin hoop with a radius of 0.5 meters and a
rotational inertia I = mr2. How much work must be done to bring it to a stop?
A) 7.9 J.
B) 15.7 J.
C) 31.4 J.
D) 49.35 J.
E) 98.7 J.
26. Two objects are moving as shown in the figure. What is their total angular momentum about point O?
A) 0 kg.m2/s
D) 360 kg.m2/s
B) 120 kg.m2/s
E) 480 kg.m2/s
C) 240 kg.m2/s
40 m/s
3 kg
20 m/s
2.0 m
4 kg
3.0 m
O
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27. A 6 kg particle with velocity v = -2i + 5j is at x = 30 m, y = 45 m. What is the angular momentum of the particle
about the origin?
A) 150i
B) 90j
C) 240k
D) 1440k
E) 990(i + j)
28. When a star collapses after using up its hydrogen fuel, it's radius may shrink by a factor of about 40,000 (4x10 4).
Assume the star is a spinning sphere whose rotational inertia is I = (2/5)MR 2 and whose mass does not change
during the collapse. What is the ratio of the final to the original angular velocity of the star?
A) 1/200
B) 200
C) 40,000
D) 160,000
E) 1.6x109
29. A wheel is rotating freely at angular speed 900 rev/min on a shaft whose rotational inertia is negligible. A second
wheel, initially at rest and with three times the rotational inertia of the first, is suddenly coupled to the same shaft.
What is the angular speed of the resultant combination of the shaft and two wheels?
A) 225 rev/min
D) 450 rev/min
B) 300 rev/min
E) 525 rev/min
C) 375 rev/min
30. A uniform 240-g meter stick can be balanced by a 240-g weight placed at the 100-cm mark if the fulcrum
(supporting force) is placed at the point marked:
A) 75 cm
B) 60 cm
C) 50 cm
D) 40 cm
E) 80 cm
31. (FE) The system shown in the figure is in equilibrium. Assume that the pulleys have negligible friction and the two
blocks have equal weights. Draw the free body diagram for the movable pulley and find the defection D below the
horizontal. D is most nearly:
(A) 0.250 L
(C) 0.420 L
(B) 0.289 L
(D) 0.577 L
Deflection D
Movable
Pulley
(E) 1.0 L
L
L
32. A safe whose mass is 250 kg is hanging by a rope from a massless bar whose length components are a = 3 m and
b=4 m. The end of the bar near the wall is hinged and a horizontal cable attached to the wall holds up the other
end. Find the tension in the horizontal cable.
A) 333 N.
B) 1634 N.
C) 1837 N.
D) 2450 N.
E) 3267 N.
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33. At what altitude above the Earth's surface would the gravitational acceleration be 1/9 of the value at the Earth's
surface? You may need to know the gravitational constant, mass of the Earth, and radius of the Earth which are: G =
6.67x10-11 (SI), ME = 5.98x1024 kg, and RE = 6.37x106 m.
A) 57,300 km
B) 25,500 km
C) 19,100 km
D) 12,740 km.
E) 6370 km
34. A particle oscillating in simple harmonic motion is:
A) never in equilibrium because it is in motion
B) never in equilibrium because there is a force
C) in equilibrium at the ends of its path because its velocity is zero there
D) in equilibrium at the center of its path because the acceleration is zero there
E) in equilibrium at the ends of its path because the acceleration is zero there
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