PhysicsLAB: PhysicsBowl 2018 (Part 2)

AAPT Quiz
PhysicsBowl 2018 (Part 2)

26. A simple pendulum consists of a mass M attached to a string of length L of negligible mass. For this system, when undergoing small oscillations

(A) the frequency is proportional to the amplitude.
(B) the period is proportional to the amplitude.
(C) the frequency is independent of the mass M.
(D) the frequency is independent of the length L.
(E) the frequency is inversely proportional to the length L

27. Electrons flow from right to left in a wire. A proton is directly above the wire and moving upward as shown. What is the direction of the magnetic force on the proton?

(A) to the left(B) to the right(C) into the plane of the page(D) out of the plane of the page(E) toward the wire

28. At the top of a high cliff, a small rock is dropped from rest. A ball is launched straight downward with an initial speed of 36.0 m/s at a time of 2.10 s after the rock was dropped from the same cliff. When the ball has fallen 28.0 m further than the initially dropped rock, what is the speed of the ball relative to the rock?

(A) 15.0 m/s(B) 16.0 m/s(C) 20.0 m/s(D) 21.0 m/s(E) 36.0 m/s

29. An object that is 8.60 cm tall is placed in front of a convex mirror. The resulting image is 7.60 cm tall, and 14.2 cm from the mirror. What is the focal length of the mirror?

(A) -122 cm(B) -105 cm(C) 14.0 cm(D) -16.9 cm(E) -4.2 cm

30. A radian per second is a unit of:

(A) angular displacement(B) angular velocity(C) angular acceleration(D) angular momentum(E) rotational kinetic energy

31. A standing transverse wave is formed on a tightly stretched string. The distance between a node and an adjacent antinode is:

(A) 1/8 wavelength(B) 1/4 wavelength(C) 1/2 wavelength(D) 1 wavelength(E) unable to be determined without more information.

32. For a negative point charge, the electric field vectors:

(A) circle the charge
(B) point radially in toward the charge
(C) point radially away from the charge
(D) pass directly through the charge
(E) cross at infinity

33. A torque of 150 Newton-meters causes the driveshaft of a car to rotate at 450 radians per second. How much power is produced by this torque?

(A) 53,300 W(B) 67,500 W(C) 70,000 W(D) 72,500 W(E) 75,000 W

34. For the hydrogen atom, which series describes electron transitions to the N=1 orbit, the lowest energy electron orbit?

(A) Lyman series(B) Balmer series(C) Paschen series(D) Curie series(E) Bohr series

35. 200 turns of wire are wrapped on a square frame with sides 18 cm. A uniform magnetic field is applied perpendicular to the plane of the coil. If the field changes uniformly from 0.50 T to 0 in 8.0 s, find the average value of the induced emf.

(A) 2.05 V(B) 4.05 V(C) 0.205 V(D) 0.405 V(E) 0.605 V

36. A 0.30 kg mass is suspended on a vertical spring. In equilibrium the mass stretches the spring 2.0 cm downward. The mass is then pulled an additional distance of 1.0 cm down and released from rest. What is the period of oscillation?

(A) 0.14 s(B) 0.28 s(C) 0.024 s(D) 0.046 s(E) 0.064 s

37. An electron is traveling due north and has a speed of 4.0 x 10⁵ m/s. It enters a region where the Earth's magnetic field has the magnitude 5.0 x 10^-5 T to the north and directed downward at 45° below the horizontal. What is the magnitude of the force acting on the electron?

(A) 2.3 x 10^-18 N(B) 3.2 x 10^-18 N(C) 4.2 x 10^-18 N(D) 2.5 x 10^-19 N(E) 3.23 x 10^-19 N

38. Why does the sky appear to be more blue when looking directly overhead than it does when looking toward the horizon?

(A) The atmosphere is denser at higher altitude than it is at the Earth's surface.
(B) The temperature of the upper atmosphere is higher than it is at the Earth's surface.
(C) There are fewer clouds directly overhead than near the horizon.
(D) The sunlight travels over a longer path at the horizon, resulting in more scattering.
(E) The sunlight entering the atmosphere from directly above undergoes greater refraction and dispersion.

39. A mass that is in simple harmonic motion obeys the following position versus time equation:

y = (0.50 m) sin (π/2 t) where t is in seconds.

What is the period of vibration of this mass?

(A) 1.0 s(B) 2.0 s(C) 3.0 s(D) 4.0 s(E) 5.0 s

40. Which of the following wavelengths (in nm) of electromagnetic radiation will produce photoelectrons of the least kinetic energy if the radiation is incident on a material with a work function of 4.80 eV?

(A) 992(B) 496(C) 248(D) 124(E) 62

All Division 1 students STOP HERE. Your last answer should be for #40. Numbers #41-#50 should remain blank for Division 1 students.
All Division 2 students continue to Questions #41 – #50.

41. An object of mass m is initially at rest. After this object is accelerated to a speed of 2.40 x 10⁸ m/s, it collides with and sticks to a second object of mass m that is at rest. Immediately after the collision, what is the common speed of the two masses?

(A) 2.25 x 10⁸ m/s(B) 1.80 x 10⁸ m/s(C) 1.66 x 10⁸ m/s(D) 1.50 x 10⁸ m/s(E) 1.20 x 10⁸ m/s

42. Two moles of an ideal gas absorbs 2100 J of heat during an isobaric process. If the gas changes temperature by 36 C^o during the process, which one of the following choices could identify the gas?

(A) Carbon monoxide(B) Water vapor(C) Ammonia(D) Helium(E) Hydrogen sulfide

43. In August of 2017, the gravitational waves from the collision and merger of two neutron stars were detected. After their collision, several forms of electromagnetic radiation were subsequently detected. What was the first type of electromagnetic radiation detected after the gravitational waves were detected?

(A) Gamma rays(B) Visible light(C) Radio waves(D) X-rays(E) Microwaves

44. Which of the following terms/quantities is most closely associated with “the measure of resistance of an object to length change under lengthwise tension or compression”?

(A) Bulk modulus(B) Plastic deformation(C) Shear modulus(D) Elastic limit(E) Young’s modulus

45. According to Lenz's law, the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

(A) Enhance the effect which produces it.
(B) Produce a greater heating effect.
(C) Oppose the greatest voltage.
(D) Oppose the effect which produces it.
(E) Enhance the greatest voltage.

46. When an ideal gas is taken through an isochoric process,

(A) ΔU=0(B) W=0(C) Q=0(D) ΔU=W(E) none of the above

47. The existence of the neutrino was proposed to explain

(A) alpha decay(B) gamma emission(C) beta decay(D) fission(E) fusion

48. A series RC circuit has a resistance of 2.00 Ω and a capacitance of 0.010 F. A student plots the natural log of the current in the circuit as a function of time while the capacitor is charging. Which one of the following choices best represents the numerical value associated with the slope of the resulting line?

(A) 0.02(B) -0.02(C) 50(D) -50(E) 0.5

49. A particle has a total energy of 500 MeV and a linear momentum of 300

What is the mass of the particle?

(A) 800

(B) 583

(D) 267

(E) 200

50. Two spheres are heated to the same temperature and allowed to radiate energy to identical surroundings. The spheres have the same emissivity, but one sphere has twice the diameter of the other. If the smaller sphere radiates energy at a rate P, at what rate will the larger sphere radiate energy?

(A) P(B) 2 P(C) 4 P(D) 8 P(E) 16 P

All Division 2 students STOP HERE. Your last answer should be for #50.