Physics II Exam 1

Two horizontal pipes are the same length, but pipe B has twice the diameter of pipe A. Water undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe A is Q = change V/change t , what is the flow rate in pipe B?

16 Q

Consider a pipe of length L that is open at both ends. What are the wavelengths of the three lowest-pitch tones produced by this pipe?

2 L , L , 2 L /3

Two horizontal pipes have the same diameter, but pipe B is twice as long as pipe A. Water undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe B is Q = V/t what is the flow rate in pipe A?

2Q

Consider a pipe of length L that is open at one end and closed at the other end. What are the wavelengths of the three lowest-pitch tones produced by this pipe?

4 L , 4 L /3, 4 L /5

When a box rests on a round sheet of wood on the ground, it exerts an average pressure p on the wood. If the wood is replaced by a sheet that has half the diameter of the original piece, what is the new average pressure?

4p

A styrofoam sphere of radius R has a density p. You now carefully compress the sphere so its radius is R /2. What is the density of the compressed sphere?

8p

When a heavy metal block is supported by a cylindrical vertical post of radius R, it exerts a force F on the post. If the diameter of the post is increased to 2 R , what force does the block now exert on the post?

F

The intensity of the waves from a point source at a distance d from the source is I . What is the intensity at a distance 2 d from the source?

I/4

What is the wavelength of the wave shown in the figure?

It cannot be determined from the given information.

Two pure tones are sounded together and a particular beat frequency is heard. What happens to the beat frequency if the frequency of one of the tones is increased?

It could either increase or decrease.

The water pressure to an apartment is increased by the water company. The water enters the apartment through an entrance valve at the front of the apartment. Where will the increase in the static water pressure be greatest when no water is flowing in the system?

It will be the same at all faucets.

If atmospheric pressure increases by an amount change p , which of the following statements about the pressure in a lake is true? (There could be more than one correct choice.)

The absolute (total) pressure increases by change p The gauge pressure does not change.

As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it if it started above the surface of the water?

The buoyant force first increases and then remains constant

Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?

The buoyant force is the same in both cases

A closed cubical chamber resting on the floor contains oil and a piston. If you push down on the piston hard enough to increase the pressure just below the piston by an amount change p, which of the following statements is correct? (There could be more than one correct choice.)

The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber. The pressure everywhere in the oil will increase by change p.

An pipe of length L that is open at both ends is resonating at its fundamental frequency. Which statement about the sound is correct?

The wavelength is 2 L and there is a displacement node at the pipe's midpoint.

A pipe of length L that is closed at one end and open at the other end is resonating at its fundamental frequency. Which statement about the sound is correct?

The wavelength is 4 L and there is a displacement antinode at the pipe's open end.

Why does the intensity of waves from a small source decrease with the square of the distance from the source?

The waves spread out as they travel.

Substance A has a density of 3 g/cm3 and substance B has a density of 4 g/cm3 . In order to obtain equal masses of these two substances, what must be the ratio of the volume of A to the volume of B?

VA/VB = 4/3

In a resonating pipe that is open at both ends, there

are displacement antinodes at each end

Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the water pressure greatest?

at point B

A person stands between two speakers driven by the same source. Each speaker produces a tone with a frequency of 200 Hz on a day when the speed of sound is 330 m/s. The person is 1.65 m from one speaker and 4.95 m from the other. What type of interference does the person perceive?

constructive

The intensity of the waves from a point source at a distance d from the source is I . At what distance from the sources is the intensity equal to 2I?

d / sqr root 2

A boat loaded with rocks is floating in a swimming pool. If the rocks are thrown into the pool, the water level in the pool, after the rocks have settled to the bottom,

falls

A steel ball sinks in water but floats in a pool of mercury, which is much denser than water. Where is the buoyant force on the ball greater?

floating on the mercury

As you are moving very quickly toward a speaker emitting a pure tone, which characteristics of the sound get larger? (There may be more than one correct choice.)

frequency loudness

Consider a brick that is totally immersed in water, with the long edge of the brick vertical. The pressure on the brick is

greatest on the bottom of the brick

In many cartoon shows, a character runs off a cliff, realizes his predicament, and lets out a scream. He continues to scream as he falls. If the physical situation is portrayed correctly, from the vantage point of an observer at the foot of the cliff, the pitch of the scream as he falls should be

higher than the original pitch and increasing as he falls.

An air bubble underwater has the same pressure as that of the surrounding water. As the air bubble rises toward the surface (and its temperature remains constant), the volume of the air bubble

increases

In a resonating pipe that is open at one end and closed at the other end, there

is a displacement node at the closed end and a displacement antinode at the open end.

A piece of wood is floating in a bathtub. A second piece of wood sits on top of the first piece, and does not touch the water. If the top piece is taken off and placed in the water, what happens to the water level in the tub?

it does not change

A piece of iron rests on top of a piece of wood floating in a bathtub. If the iron is removed from the wood, and kept out of the water, what happens to the water level in the tub?

it goes down

Salt water is denser than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the volume of water displaced in the salt water is

less

A string fixed at both ends is vibrating in one of its harmonics. If we now increase only the frequency at which the string is vibrating, which of the following characteristics do we also increase? (There could be more than one correct choice.)

none of the above

You double your distance from a sound source that is radiating equally in all directions. What happens to the intensity of the sound? It reduces to

one-fourth its original value.

An organ pipe of length L that is open at one end resonates in its third harmonic with a wavelength of 2 L /3. Is the other end of the pipe closed or open?

open

A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is p . You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid. What is the density of the enlarged sphere?

p

What characteristics of a sound wave are related to the "pitch" of a musical note? (There could be more than one correct choice.)

period wavelength frequency

A wooden block contains some nails so that its density is exactly equal to that of water. If it is placed in a tank of water and released from rest when it is completely submerged, it will

remain where it is released.

A 10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. Which one has the greater buoyant force on it?

the aluminum

When a guitar is tuned to adjust it pitch, what is it that is changed?

the frequency of the fundamental.

A 50-cm3 block of wood is floating on water, and a 50-cm3 chunk of iron is totally submerged in the water. Which one has the greater buoyant force on it?

the iron

Consider the standing wave on a guitar string and the sound wave generated by the string as a result of this vibration. What do these two waves have in common? (There may be more than one correct choice.)

they have same period they have same frequency

Suppose that a sound source is emitting waves uniformly in all directions. If you move to a point twice as far away from the source, the frequency of the sound will be

unchanged

A string of mass m is under tension, and the speed of a wave in the string is v . What will be the speed of a wave in the string if the mass of the string is increased to 2 m but with no change in the length or tension?

v / sqr root 2

A string of length L is under tension, and the speed of a wave in the string is v . What will be the speed of a wave in the string if the length is increased to 2 L but with no change in the mass or tension?

v sqr root 2

When a certain string is under tension T , the speed of a wave in the string is v . What will be the speed of a wave in the string if the tension is increased to 2 T without changing the mass or length of the string?

v sqr root 2