PhysicsLAB: PhysicsBowl 2025 (Part 2)

AAPT Quiz
PhysicsBowl 2025 (Part 2)

26. Auroras produced in the Earth’s atmosphere often occur following a phenomenon known as a CME, which is an abbreviation for …

a. Carbon Molecule Excitation
b. Celestial Magnetic Event
c. Coronal Mass Ejection
d. Cosmic Microwave Energy
e. Coupled Monopolar Electromagnetism

27. A block of wood is given a certain speed at the bottom of a rough ramp. The block slides a certain distance up the ramp and returns to the point from which it was launched. Let t_up represent the time it takes the block to travel up the ramp to its highest point and t_down represent the time it takes the block to travel down the ramp to the bottom. Let a_up represent the magnitude of the block’s acceleration while traveling up the ramp and a_down represent the block’s acceleration while traveling down the ramp. Which of the following correctly compares these quantities?

28. A container filled with water is placed in an elevator. When the elevator is at rest, a small block floats in the water with 50% of its volume submerged.

If the elevator accelerates up with a constant acceleration of 0.1g, what percentage of the block’s volume will be submerged? Treat water as an incompressible fluid.

a. 5%b. 45%c. 50%d. 55%e. 95%

29. M_A has a mass of 10 kg and slides to the right at 3 m/s across a level, frictionless surface towards M_B that has a mass of 6 kg and is initially at rest. There is a massless, ideal spring with k = 540 N/m on the left side of M_B. The spring is initially compressed and held so that it will not release until the impact with M_A. After the collision, M_A is a rest.

How far was the spring compressed from its natural length in meters?

a. 0.333b. 0.200c. 0.250d. 0.111e. 0.063

30. The diagram below shows an inverted test tube over a sample of a radioactive material. Helium has collected in the test tube.

The presence of helium indicates that the sample is most probably undergoing the process of

a. alpha decaya. alpha decayc. beta decayd. proton decaye. gamma emission

31. A mass, m =1.0 kg, is pulled on a horizontal table by a force F = 2 N, directed to the right. A small kinetic friction force F_friction = 1 N acts on the mass while it is being pulled and the mass accelerates to the right with an acceleration, a₁ = 1 𝑚/𝑠². The system then undergoes two changes:

i) m₁ is doubled
ii) F_friction is doubled

Which of the following statements about the new acceleration, a₂, is correct?

a. The magnitude of a₂ increases by a factor of 2.b. The magnitude of a₂ decreases by a factor of 0.5.c. 0> a2<a1.d. 0>a₁<a₂.e. a₂= 0 𝑚/𝑠².

32. The diagram below shows a ball rolling down an incline.

The direction of the normal force that the incline exerts on the ball is…

a. perpendicular to the surface.
b. about 75 degrees measured from the surface.
c. parallel to the surface.
d. about 115 degrees measured from the surface.
e. about 180 degrees measured from the surface.

33. A sealed cylindrical container of height h is divided into two equal volumes by a frictionless, thermally insulated piston of negligible mass. The lower half of the container contains n moles of an ideal monatomic gas at an initial temperature T₁ and pressure P₁. The upper half is initially evacuated (vacuum). The piston is released, allowing the gas to expand into the entire container. Assuming the process is adiabatic, and the gas reaches a new equilibrium state, what is the final temperature T_f of the gas?

34. A transverse standing wave containing four loops is created on a string that is fixed at both ends. The string has a linear density μ. A second string with the same length and a linear density of 4μ now replaces the first string. When placed under the same tension and vibrated at the same frequency, the standing wave produced on the second string will contain …

a. 1 loop.b. 2 loops.c. 4 loops.d. 8 loops.e. 16 loops.

35. An airplane is flying in a vertical loop.

At the bottom of the loop, the forces on the pilot are such that…

a. F_N > F_g.b. F_N = F_g.c. F_N < F_g.d. F_N cannot be determined without knowing the plane’s speed.e. F_g decreases.

36. A solid disk of mass, M, moment of inertia, I, and radius, R, is at rest with its circular face on a horizontal, frictionless table as shown in this overhead view.

A rope is wrapped around the disk tightly and pulled with a force of T. The disk moves linearly and rotationally as the force, T, accelerates the disk along the table. After the disk has accelerated some distance, determine the ratio of the translational Kinetic Energy to the total Kinetic Energy of the disk. (KE_{translational} /KE_total)

a. I/MR²b. MR²/Ic. I³/MR²d. I/(MR²+I)e. MR²/(MR²+I)

37. The graph shows the momentum of a particle as a function of time.

What net impulse acted on the particle from t = 0.0 sec to t = 9.0 sec?

a. 0.0 N•sb. 1.3 N•sc. 2.0 N•sd. 12 N•se. 32 N•s

38. Which of the following statements about the electric field inside a charged conductor at electrostatic equilibrium is true?

a. The strength increases uniformly with the distance from the center of the conductor.
b. The strength decreases uniformly with the distance from the center of the conductor.
c. The strength is a uniform, non-zero value everywhere.
d. The strength is zero everywhere.
e. The strength varies randomly from point to point.

39. The diagram shown represents an N-type silicon semiconductor connected to a battery. A very small amount of antimony, which has five valence electrons, had previously been added to the silicon crystal. This process produced

a. an excess of free protons.b. an excess of free electrons.c. more resistance.d. less resistance.e. a higher emf.

40. A container of ideal gas undergoes a Carnot heat engine cycle in the order shown below.

Process 1 – Reversible isothermal expansion
Process 2 – Reversible adiabatic expansion
Process 3 – Reversible isothermal compression
Process 4 – Reversible adiabatic compression

The gas has returned to its original state at the end of the cycle. Let Q_n represent the amount of heat exchanged on process n. Which of the following correctly calculates the efficiency of this engine?

a. 1 – Q₁ / Q₂b. 1 – Q₂ / Q₃c. 1 – Q₃ / Q₄d. 1 – Q₃ / Q₁e. 1 – Q₄ / Q₁

All Division I students, STOP HERE.
All Division II students continue questions #41 through #50.
*** Treat g = 10 m/s² in ALL problems, #1-#50.

41. The transverse wave shown below is traveling from left to right in a string.

The direction of the velocity of the string at point P is:

a. leftb. rightc. upd. downe. unknown

42. An electromagnetic wave has a magnetic field given by the expression (in Cartesian coordinates)

At time 𝑡 = 0 and position 𝑥 = 𝑦 = 𝑧 = 0, what is the direction of the electric field associated with this wave?

a. + xb. – xc. + yd. – ye. + z

43. An object is placed in front of a convex lens at a distance less than F. The image produced by the lens is…

a. real, inverted, and smaller than the object.
b. real, inverted, and larger than the object.
c. virtual, upright, and larger than the object .
d. virtual, upright, and smaller than the object.
e. virtual, inverted, and larger than the object.

44. An object with mass M moves due East on a frictionless horizontal surface with a speed of V. A second object of mass (1/2) 𝑀 has a speed of 3V. The two objects collide and stick together. If the objects are moving due South after the collision, with what speed are they moving?

45. The following expressions are non-mks units in physics. Identify the physical quantity that can be measured with the following units:

(1) GeV, (2) GeV/c, (3) GeV/c2

a. (1) Charge (2) Velocity (3) Mass
b. (1) Energy (2) Linear Momentum (3) Mass
c. (1) Mass (2) Angular Momentum (3) Torque
d. (1) Energy (2) Angular Momentum (3) Charge
e. (1) Energy (2) Linear Momentum (3) Torque

46. Two resistors are connected in parallel to an ideal voltage source using wires of negligible resistance. Resistor B produces thermal energy at four times the rate of resistor A. Which of the following could account for this difference?

a. Resistor B has one-fourth the resistance of resistor A.
b. Resistor B has one-half the resistance of resistor A.
c. Resistor B has twice the resistance of resistor A.
d. Resistor B has four times the resistance of resistor A.
e. Resistor B has twice the potential difference of resistor A.

47. Which of the following statement(s) can be associated with Bohr’s theory of the atom?

I. An electron orbiting the nucleus can change its energy continuously.
II. An electron orbiting the nucleus emits energy and falls into the nucleus.
III. An electron orbits the nucleus without radiating energy and can change its energy only by a specific, quantized amount, when it moves between the orbits.
IV. Electrons can only orbit the nucleus in specific circular orbits with fixed angular momentum and energy.

a. I and IIb. II and IVc. II and IIId. III and IVe. I, II, III and IV

48. An incredibly energetic spaceship has a “proper length” of L = 200 m, as determined by an observer on board the ship. It is traveling at a speed 0.97c relative to the Earth. Assuming the spaceship travels parallel to its length L, what is the length of the spaceship as measured by a physicist that observes the ship from Earth?

a. 200 mb. 194 mc. 48.6 md. 206 me. 97.0 m

49. Point charges +q and –q are fixed in place on the x-axis at x = +d and x = -d, respectively.

At x = 0, their Net Electric Field _______ and their Total Electric Potential _______.

a. is zero, is zero
b. points in the positive x-direction, is positive
c. points in the negative x-direction, is negative
d. points in the positive x-direction, is zero
e. points in the negative x-direction, is zero

50. A waterproof speaker placed at the bottom of a swimming pool emits a sound wave that travels toward the surface of the water. In the water, the sound wave has a frequency, f_water, a wavelength, λ_w_ater, and wave speed, v_water. When the sound wave enters the air, it has a frequency, f_air, a wavelength, λ_a_ir, and a wave speed, v_air.

Which one of the following relationships correctly compares the frequencies, wavelengths, and wave speeds of the waves in the air and water?