Physics Olympiad
Entia non multiplicanda sunt praeter necessitatem
1998 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 may not be shared.
Your grade 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 m e= 9.1 x 10-31 kg
mass of proton m p= 1.7 x 10-27 kg
electronic charge e= 1.6 x 10-19 C
speed of light c= 3.0 x 108 m/s
Coulomb's constant k= 9.0 x 109 N·m2/C2
permittivity constantε0=8.9 x 10-12 C2/N·m2
permeability constantμ0= 41 x 10-7 T·m/A
gravitational constant G= 6.7 x 10-11 N·m2/kg2
mass of Earth M E= 6.0 x 1024 kg
radius of Earth R E= 6.4 x 106 m
gravitational field at Earth’s surface g= 9.8 N/kg
speed of sound (20o C)v s= 340 m/s
DO NOT OPEN THIS TEST UNTIL YOU ARE INSTRUCTED TO BEGIN
Copyright ? 1998, AAPT
downstream by a river current of constant velocity v. The helicopter is at a height of 9.8 m. The swimmer is 6.0 m upstream from a point directly under the helicopter when the life preserver is released. It lands 2.0 m in front of the swimmer. How fast is the current flowing? Neglect air resistance.
A. 13.7 m/s
B. 9.8 m/s
C. 6.3 m/s
D. 2.8 m/s
E. 2.4 m/s
4. A child tosses a ball directly upward. Its total time in the air is T. Its maximum height is H. What is its height after it has been in the air a time T/4? Neglect air resistance.
A. (1/4) H
B. (1/3) H
C. (1/2) H
D. (2/3) H
E. (3/4) H
5. A whiffle ball is tossed straight up, reaches a highest point, and falls back down. Air resistance is not negligible. Which of the following statements are true?
I.The ball’s speed is zero at the highest point.
II.The ball’s acceleration is zero at the highest point.
III.The ball takes a longer time to travel up to the highest point than
to fall back down.
A. I only
B. II only
C. I & II only
D. I & III only
E. I, II, & III
6. A pendulum is attached to the ceiling of an elevator car. When the car is parked, the pendulum exhibits a period of 1.00 s. The car now begins to travel upward with an upward acceleration of 2.3 m/s 2. During this part of the motion, what will be the approximate period of the pendulum?A. 0.80 s
B. 0.90 s
C. 1.00 s
7. Two identical blocks of weight W
The lower block is pulled to the right with a force What is the largest force F block starts to slip?A. μW
B. (3/2) μW
C. 2 μW
8. An object placed on an equal arm balance requires 12 kg to balance it. When placed on a spring scale, the scale reads 120 N. Everything (balance, scale, set of masses, and the object) is now transported to the moon where the gravitational force is one-sixth that on Earth. The new readings of the balance and the spring scale (respectively) are:A. 12 kg, 20 N
B. 12 kg, 120 N
C. 12kg, 720 N
D. 2 kg, 20 N
E. 2 kg, 120 N
A. 2S
B. S
C. S/2
D. S/3
E. S/4
minimum, then:
A. car R is still at rest.
B. car Z has come to rest.
C. both cars have the same kinetic energy.
D. both cars have the same momentum.
E. the kinetic energy of the system has reached a minimum.
11. Two ice skaters, a 200 lb man and a 120 lb woman, are initially hugging on a frictionless level
the woman moved in that time?A. 8.0 m
B. 6.5 m
C. 5.0 m
following statements is true?I.II.the collision.
III.
A. I only
B. II only
(mass m 1) is initially moving with speed v o . It collides with and sticks to an initially stationary block (#2) of mass m 2 = 9 m 1.
13. What is the speed of the two blocks after the collision?A. v o
B. (9/10) v
o
C. (8/9) v o
D. (1/9) v o
E. (1/10) v o
14. What fraction of the initial kinetic energy of the system is converted to other forms (heat,sound, ...) as a result of the collision?A. 1 %
B. 10 %
C. 50 %
D. 90 %
E. 99 %15. Three identical objects of mass M are fastened to a massless rod of length L as shown. The array rotates about the center of the rod. Its rotational inertia is A. (1/2) ML 2
B. ML 2
C. (5/4) ML 2
D. (3/2) ML 2
E. 3 ML 2
and outer radius Which of the A. cos θ = r/R
B. sin θ = r/R
C. T = W
D. T = W sin θ
E. T = W cos θ
23. A thin film of thickness t
following thicknesses t
air? Hint: Light undergoes a 180o
material with a higher index of refraction.A. 160 nm
B. 240 nm
C. 360 nm
D. 480 nm
24. An object is placed 12 cm in front of a spherical mirror. The image is right side up and is two times bigger than the object. The image is:A. 6 cm in front of the mirror and real.B. 6 cm behind the mirror and virtual.C. 12 cm in front of the mirror and virtual.D. 24 cm in front of the mirror and virtual.E. 24 cm behind the mirror and virtual.
charged parallel plates. Both are closer to the positive plate than the negative plate. See diagram to the right. Which of the following statements is true?
I.The force on the proton is greater than the force on the electron.
II.The potential energy of the proton is greater than that of the electron.III.
The potential energy of the proton and the electron is the same.A. I only
B. II only
C. III only
D. I & II only
E. I & III only
27. In the electrical circuit shown to the right, the current through the 2.0 ? resistor is 3.0 A. The emf of the battery is about A. 51 V
B. 42 V
C. 36 V
D. 24 V
E. 21 V
28. An ion with a charge q , mass m , and speed v enters a magnetic field B and is deflected into a path with a radius of curvature R . If an ion with charge q , mass 2m , and speed 2v enters the same magnetic field, it will be deflected into a path with a radius of curvature A. 4 R
B. 2 R
C. R
D. (1/2) R
E. (1/4) R
magnetic force on the wire points A. south
B. north
C. east
D. west
E. downward
6.0?6.0?2.0?3.0?
1998 MULTIPLE CHOICE SCREENING TEST
ANSWER KEY
1. E11. C21. D
2. B12. C22. D
3. D13. E23. C
4. E14. D24. E
5. A15. A25. D
6. B16. A26. B
7. E17. C27. B
8. A18. B28. A
9. C19. A29. B
10. E20. C30. D
