Download 2003 aapt physics olympiad

2003 AAPT PHYSICS OLYMPIAD
Entia non multiplicanda sunt praeter necessitatem
2003 MULTIPLE CHOICE SCREENING TEST
30 QUESTIONS - 40 MINUTES
INSTRUCTIONS
DO NOT OPEN THIS TEST UNTIL YOU ARE TOLD TO BEGIN
This test contains 30 multiple choice questions. Your answer to each question must be marked
on the optical mark answer sheet that accompanies the test. Only the boxes preceded by
numbers 1 through 30 are to be used on the answer sheet.
Select the single answer that provides the best response to each question. Please be sure to use a
No. 2 pencil and completely fill the box corresponding to your choice. If you change an answer,
the previous mark must be completely erased.
A hand-held calculator may be used. However, any memory must be cleared of data and
programs. Calculators are not to be shared.
Your score on this multiple choice test will be your number of correct answers. There is no
penalty for guessing. It is to your advantage to answer every question.
The values of some possibly useful constants are given below:
mass of electron
Atomic mass unit (1 proton or 1 neutron)
electronic charge
speed of light
Coulomb’s constant
Planck's constant
permittivity constant
permeability constant
gravitational constant
mass of Earth
radius of Earth
latent heat of fusion of water
specific heat of water
gravitational field at Earth’s surface
speed of sound (20o C)
me
u
e
c
k
h
εo
µo
G
ME
RE
Lf
c
g
vs
=
=
=
=
=
=
=
=
=
=
=
=
=
=
=
9.1 x 10-31 kg
1.7 x 10-27 kg
1.6 x 10-19 C
3.0 x 108 m/s
9.0 x 109 N.m2/C2
6.6 x 10-34 J.s
8.9 x 10-12 C2/N.m2
4π x 10-7 T.m/A
6.7 x 10-11 N.m2/kg2
6.0 x 1024 kg
6.4 x 106 m
3.3 x 105 J /kg
4.2 x 103 J/kgCo
9.8 N/kg
340 m/s
DO NOT OPEN THIS TEST UNTIL YOU ARE TOLD TO BEGIN
Copyright  2003, American Association of Physics Teachers.
2003 Physics Olympiad
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THE NEXT THREE QUESTIONS REFER TO THE FOLLOWING SCENARIO
Three blocks (A, B, and C) are each pushed by equal forces, F, frictionlessly across a horizontal
surface for a distance of 2 meters. The mass of block A is greater than block B, and the mass of
block B is greater than block C.
1.
Which block will be traveling the fastest after the 2 meter push?
A) Block A
D) All blocks will be moving with the same speed
B) Block B
E) It depends on the actual masses of the blocks
C) Block C
2.
Which of the blocks would have the greatest kinetic energy at the end of the 2 meter
push?
A) Block A
D) All blocks will have the same kinetic energy
B) Block B
E) It depends on the actual masses of the blocks
C) Block C
3.
Which of the blocks will have received the greatest impulse during the 2 meter push?
A) Block A
D) All blocks will have the same impulse
B) Block B
E) It depends on the actual masses of the blocks
C) Block C
4.
A skydiver is falling at terminal velocity before opening her parachute. After opening
her parachute, she falls at a much smaller terminal velocity. How does the total upward force
before she opens her parachute compare to the total upward force after she opens her parachute?
A) the ratio of the forces is equal to the ratio of the velocities
B) the ratio of the forces is equal to the inverse ratio of the velocities
C) the upward force with the parachute will depend on the size of the parachute
D) the upward force before the parachute will be greater because of the greater velocity
E) the upward force in both cases must be the same
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5.
The gravitational force on a textbook at the top of Pikes Peak (elevation 14,100 ft.) is 40
newtons. What would be the approximate gravitational force on the same textbook if it were
taken to twice the elevation?
A) 5 N
B) 10 N
C) 20 N
D) 40 N
E) 80 N
6.
A cube of aluminum has side length 0.10 m. It is dropped into a deep swimming pool of
water with density 1.00 x 103 kg/m3. The cube comes gently to rest at the bottom of the pool. If
the density of the aluminum is 2.7 x 103 kg/m3, the magnitude of the buoyant force acting on the
aluminum is:
A) 26.6 N
B) 9.8 N
C) 2.7 N
D) 1.0 N
E) 0 N
7.
The diagrams below show four cannons firing shells with different masses at different
angles of elevation. The horizontal component of the shell's velocity is the same in all four
cases. In which case will the shell have the greatest range if air resistance is neglected?
A) Cannon A
B) Cannon B only
C) Cannon C only
D) Cannon D
E) Both cannons B and C have the greatest range
8.
Each of the diagrams below represents two weights connected by a massless string which
passes over a massless, frictionless pulley. In which diagram will the magnitude of the
acceleration be the largest?
A.
2003 Physics Olympiad
B.
C.
D.
E.
3
9. A uniform ladder in static equilibrium leans against a
frictionless wall. The ladder has length L and mass M. Given
that the angle between the ladder and floor is 30o degrees, what
would be the value of the coefficient of static friction (µs)
between the ladder and the ground?
1
1
A) µ s ≥
D) µ s ≥
2
3
2
E) µ s ≥ 3
B) µ s ≥
3
3
C) µ s ≥
2
10.
A roller coaster car moves along a track as shown. At point A, the roller coaster car is
moving with a speed of 10 m/s. If friction is negligible, about how fast would the car be moving
at point B?
A) 14 m/s
B) 20 m/s
C) 22 m/s
D) 26 m/s
E) 31 m/s
11.
A laboratory cart with a mass of m and velocity v runs headlong into a stationary spring
bumper and compresses the spring. If the spring has a spring constant k, what is the maximum
compression of the spring?
mv 2
m
mv
mv
A) v
B)
C)
E)
D) mv k
k
k
2k
2k
12.
A meter stick is supported at each end by a spring scale. A heavy mass is then hung on
the meter stick so that the spring scale on the left hand side reads four times the value of the
spring scale on the right hand side. If the mass of the meter stick is negligible compared to the
hanging mass, how far from the right hand side is the large mass hanging?
A) 25 cm
B) 50 cm
C) 67 cm
D) 75 cm
E) 80 cm
2003 Physics Olympiad
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THE NEXT TWO QUESTIONS REFER TO THE FOLLOWING SCENARIO
A figure skater has a moment of inertia of 4.0 kg.m2 with her arms outstretched. If she begins a
spin at 3.0 rad/s with her arms outstretched and then brings her arms in tight to her body, her rate
of spin increases to 7.0 rad/s in 2.5 seconds. You may ignore friction and air resistance.
13.
spin.
14.
As the skater brings her arms in tight to her body, what torque is applied to increase her
A) 2.7 N.m
B) 4.0 N.m
C) 5.3 N.m
D) 9.3 N.m
E) no torque is applied to increase her spin
What is the moment of inertia of the skater with her arms tight to her body?
A) 0.73 kg.m2
B) 1.7 kg.m2
C) 2.8 kg.m2
D) 7.5 kg.m2
E) 9.4 kg.m2
15.
Two identical spheres carry identical electric charges. If the spheres are set a distance d
apart they repel one another with a force F. A third sphere, identical to the other two but initially
uncharged is then touched to one sphere and then to the other before being removed. What
would be the resulting force between the original two spheres?
3
5
1
3
1
A) F
B) F
C) F
D) F
E) F
4
8
2
8
4
16.
A conventional electric current flows due east in a high voltage power line. What would
be the direction of the resulting magnetic field directly below the power line?
A) north
B) east
C) south
D) west
E) up
17.
Two parallel metal plates 0.04 meters apart are connected to a 1.5 volt battery. When
fully charged, each metal plate has a charge of magnitude 9.0 x 10-4 coulombs. What is the
capacitance of the two plates?
A) 1.5 x 10-2 F
B) 1.2 x 10-3 F
C) 3.0 x 10-4 F
D) 6.0 x 10-4 F
E) 9.0 x 10-4 F
18.
An electron travels so that its total energy is twice its rest energy (0.511 MeV). What is
the speed of the electron?
1
3
3
8
8
A) v = c
B) v = c
C) v =
D) v = c
E) v =
c
c
2
4
2
9
3
19.
An alpha particle is accelerated to a velocity v in a particle accelerator by a potential
difference of 1200 V. Which of the following potential differences would be needed to give the
alpha particle twice the velocity?
A) 7200 V
B) 4800 V
C) 4100 V
D) 2400 V
E) 1700 V
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20.
A battery, an ammeter,
three resistors, and a switch are
connected to form the simple
circuit shown to the right.
When the switch is closed what
would happen to the potential
difference across the 15 ohm resistor?
A) it would equal the potential difference across the 20 ohm resistor
B) it would be twice the potential difference across the 30 ohm resistor
C) it would equal the potential difference across the 30 ohm resistor
D) it would be half the potential difference across the 30 ohm resistor
E) none of the above
21.
A sample of an ideal monatomic gas is confined in a rigid 0.008 m3 container. If 40
joules of heat energy were added to the sample, how much would the pressure increase?
A)
5 Pa
D) 3,333 Pa
B) 320 Pa
E) 5000 Pa
C) 1,600 Pa
THE NEXT TWO QUESTIONS REFER TO THE FOLLOWING SCENARIO
A 9-volt battery is connected to four resistors to form a simple circuit as shown below.
22.
23.
What would be the current at point E in the circuit?
A) 2 amp
B) 4 amp
C) 5 amp
D) 7 amp
What would be the potential at point B with respect to point D?
A) +2 V
B) +4 V
C) +5 V
D) +7 V
E) 9 amp
E) +9 V
24.
A beam of light from the air is incident on a transparent block of material. The angle of
incidence is 49o while the angle of refraction is 30o. What is the velocity of light in the
transparent material?
A) 1.8 x 108m/s B) 2.0 x 108m/s C) 2.3 x 108m/s D) 3.0 x 108m/s E) 4.5 x 108m/s
2003 Physics Olympiad
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25.
An electromagnetic wave is moving to the right. At one
instant at point P, the electric field vector E is pointing towards
the top of the page. In which direction would the magnetic field
vector B point at this moment?
A) to the right
B) to the left
C) into the paper
D) out of the paper
E) towards the bottom of the paper
26.
An object is placed 60 cm from a convex converging lens. The image produced is
inverted and half the size of the object. What would be focal length of the lens?
A) 90 cm
B) 60 cm
C) 45 cm
D) 30 cm
E) 20 cm
27.
A transmission diffraction grating is ruled with 5000 lines per cm. Through what angle
will the first order maxima be deflected when light with a wavelength of 4.5 x 10-7 m strikes the
grating at an angle of incidence of 0o.
A) 5.2o
B) 6.4o
C) 13o
D) 27o
E) 34o
28.
Non-polarized light first passes through one polarizing filter and then through a second.
If the intensity of light emerging from the second filter is 12.5 % of the light that struck the first
filter, at what angle must the axes of the two filters be with respect to one another?
A) 7o
B) 30o
C) 42o
D) 600
E) 83o
29.
Assume that sodium produces monochromatic light with a wavelength of 5.89 x 10-7 m.
At what rate would a 10 watt sodium vapor light be emitting photons?
A) 3.5 x 1019 photons/s
D) 2.0 x 1019 photons/s
B) 3.0 x 1019 photons/s
E) 1.5 x 1019 photons/s
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C) 2.5 x 10 photons/s
30.
One object has twice the temperature of a second identical object. How does the rate R1
at which the first object radiates energy compare to the rate R2 at which the second object
radiates energy?
A) R1 = R2
B) R1 = 2R2
C) R1 = 4R2
D) R1 = 8R2
E) R1 = 16R2
2003 Physics Olympiad
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2002 AAPT PHYSICS OLYMPIAD
Entia non multiplicanda sunt praeter necessitatem
2003 MULTIPLE CHOICE SCREENING TEST
30 QUESTIONS - 40 MINUTES
Answers
1) C
2) D
3) A
4) E
5) D
6) B
7) D
8) A
9) C
10) C
11) A
12) E
13) E
14) B
15) D
16) A
17) D
18) C
19) B
20) C
21) D
22) A
23) A
24) B
25) D
26) E
27) C
28) D
29) B
30) E
2003 Physics Olympiad
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