Physics Bowl - Home Practice 2

A 10.0 𝑘𝑔 mass moves to the right at 8.00 𝑚/𝑠. A 5.0 𝑘𝑔 mass moves to the left at 7.00 𝑚/𝑠. With what speed does the center of mass of this two-mass system move?

• 7.67𝑚/𝑠

• 7.50 𝑚/𝑠

• 3.00 𝑚/𝑠

• 2.00 𝑚/𝑠

• 0.50 𝑚/𝑠

A tuning fork of frequency 𝑓 is placed over a long tube closed at one end producing the third lowest frequency standing wave for the tube. What frequency tuning fork would be needed to produce the fourth lowest frequency standing wave?

• 4𝑓/3

• 5𝑓/3

• 6𝑓/5

• 7𝑓/5

• 5𝑓/4

Recent excitement in the physics community came from the February, 2016 announcement from LIGO that

• alien life had been discovered on a distant planet.

• dark matter had been discovered.

• there was proof of dark energy’s existence.

• gravitational waves had been detected.

• objects had been observed to travel faster than the speed of light.

A ray of light is incident onto a thin glass lens as shown. Which one of the following arrows best indicates the path of the refracted ray?

• A

• B

• C

• D

• E

A scientist wishes to compute the amount of energy necessary to melt a known mass of a solid sample. Which quantity associated with the sample would the scientist be most interested in knowing?

• Latent heat of fusion

• Specific heat

• Coefficient of thermal expansion

• Latent heat of vaporization

• Thermal conductivity

The circuit shown has 4 identical light bulbs connected to an ideal battery. If bulb #2 were removed leaving an open circuit there, what happens to the voltage across both bulb #1 and from Q to X?

• A

• B

• C

• D

• E

A mass connected to a string forms a simple pendulum. The mass is released from rest and undergoes simple harmonic motion. Which one of the following choices correctly ranks the magnitude of the tension in the string (𝑇), the gravitational force on the mass (𝑊), and the net force acting on the mass (𝐹) when the mass swings through its lowest point?

• 𝐹 < 𝑊 = 𝑇

• 𝑊 < 𝑇 < 𝐹

• 𝑊 < 𝐹 = 𝑇

• 𝐹 < 𝑊 < 𝑇

• More information is required to answer the question.

Given the configuration of three charges, +𝑄, +𝑄, and −2𝑄, which one of the following choices best represents the direction of the electric field at the point 𝑃 and the sign of the electric potential at 𝑃 from these charges?

• A

• B

• C

• D

• E

The graph shows the magnitude of the linear momentum of two solid objects colliding on the x-axis. Which one of the following statements must be true based on the information provided?

• The objects remain stuck together after the collision.

• Object 2 experiences the greater force from the collision.

• Object 2 cannot have more mass than object 1.

• The kinetic energy loss was maximized with no external forces present in the two-object system.

• The kinetic energy of the two-object system is the same both before and after the collision.

Which one of the following choices best describes what it means for an object to be iridescent?

• The color of the object appears to change with a change in the angle of view.

• The object appears to have two images formed from it because of differences in index of refraction.

• The color of the object appears to be different based on its temperature.

• The object remains illuminated after turning off all surrounding light sources.

• The object is alive and producing light biochemically.