Physics Giancoli Misconceptional 8-15

An ideal gas undergoes an isothermal process. Which of the following statements are true?

(ii)The internal energy of the gas does not change. (iii) The average kinetic energy of the molecules does not change

Which statement is true regarding the entropy change of an ice cube that melts?

Entropy increases

Two identical bottles at the same temperature contain the same gas. If bottle B has twice the volume and contains half the numbers of moles of gas as bottle A, how does the pressure in B compare with the pressure in A?

If the second bottle has twice the volume with only half the number of moles, it would only experience one-fourth the pressure.

To make a given sound seem twice as loud, how should a musician change the intensity of the sound?

Increase the intensity by a factor of 10

How is the smoke drawn up a chimney affected when a wind is blowing outside?

Smoke rises more rapidly in the chimney

A 10-N weight is suspended by two cords (one shorter than the other). What can you say about the tension in the two cords?

The tension in the shorter cord is greater than the tension in the longer cord

Which is possible: converting (i) 100J of work entirely into 100J of near, (ii) 100 J of heat entirely into 100 J of work?

both are possible

A typical thermos bottle as a thin vacuum space between the shiny inner flask (which holds a liquid) and the shine protective outer flask, often stainless steel. The vacuum space is excellent at preventing

conduction and convection

Which of the following happens when a material undergoes a phase change?

heat flows into or out of the material

Ten grams of water is added to ten grams of ice in an insulated container. Will all of the ice melt?

more information is needed

You are driving at 75 km/h. Your sister follows in the car behind at 75 km/h. When you honk your horn, your sister hears a frequency

the same as the frequency you hear.

An object that can float in both water and in oil (whose density is less than that of water) experiences a buoyant force that is...

the same when it is floating in water or in oil

Sound waves are

(b) longitudinal waves characterized by the displacement of air molecules. (c) longitudinal waves characterized by pressure differences.

Two ideal gases, A and B, are at the same temperature. If the molecular mass of the molecules in gas A is twice that of the molecules in gas B, the molecules' root-mean-square speed is

1.4 times greater in B

An object at rest begins to rotate with a constant angular acceleration. If this object rotates through an angle theta in time T, through what angle did it rotate in the time 1/2T?

1/4theta

A rubber band is stretched by 1 cm when a force of 0.35 N is applied to each end. If instead a force of 0.70 N is applied to each end, estimate how far the rubber band will stretch from its unstretched length...

2 cm

About what percentage of the heat produced by burning gasoline is turned into useful work by a typical automobile?

20%

An object of mass M oscillates on the end of a spring. To double the period, replace the object with one of mass...

4M

A 60-kg woman stands on the very end of a uniform board, of length l, which is supported one-quarter of the way from one end and is balanced. What is the mass of the board?

60 kg

The sound level near a noisy air conditioner is 70 dB. If two such units operate side by side, the sound level near them would be

73 dB

A mass on a spring in SHM has amplitude A and period T. At what point in the motion is the velocity zero and the acceleration zero simultaneously?

Acceleration and velocity are never simultaneously zero

Which of the following is not true about an ideal gas?

All gas molecules have the same speed at a particular temperature

The linear expansion of a material depends on which of the following? The length of the material. The type of material. The change in temperature of the material. All of the above.

All of the above

When using the ideal gas law, which of the following rules must be obeyed?

Always use temperature in kelvins and absolute pressure.

When a sound wave passes from air into water, what properties of the wave will change?

Both the wave speed and wavelength

A parking garage is designed for two levels of cars. To make more money, the owner decides to double the size of the garage in each dimension (length, width, and number of levels). For the support columns to hold up four floors instead of two, how should he change the columns' diameter?

Double the area of the columns by increasing their diameter by a factor of square root of 2

For objects at thermal equilibrium, which of the following is true?

Each is at the same temperature.

Two beakers contain a mixture of ice and water at equilibrium. Beaker A has less ice than Beaker B. Which beaker is the coldest, or are they equal in temperature?

Equal

A heavy ball suspended by a cable is pulled to the side by a horizontal force F. If angle theta is small, the magnitude of the force F can be less than the weight of the ball because...

F is equal to only the x component of the tension in the cable

When you put an ice cube in a glass of warm tea, which of the following happens?

Heat flows from the tea into the ice cube.

As water flows from a low elevation to a higher elevation through a pipe that changes in diameter...

Needs more information. Does the diameter increase or decrease in size?

On a very hot day, could you cool your kitchen by leaving the refrigerator door open?

No, the heat exhausted by the refrigerator into the room is more than the heat the refrigerator takes out of the room.

Hot air is less dense than cold air. Could a hot-air balloon be flown on the moon, where there is no atmosphere?

No, there is no cold air to displace, so no buoyancy force would exist.

An ideal gas undergoes an isothermal expansion from state A to state B. In this process

Q>0,ΔU=0,W>0

Rod A has twice the diameter of rod B, but both are made of iron and have the same initial length. Both rods are now subjected to the same change in temperature (but remain solid). How would the change in the rods' lengths compare?

Rod A = rod B.

In a mixture of gases oxygen and helium, which statement is valid?

The helium atoms will be moving faster than the oxygen molecules, on average.

A small solid sphere and a small thin hoop are rolling along a horizontal surface with the same translational speed when they encounter a 20° rising slope. If these two objects roll up the slope without slipping, which will rise farther up the slope?

The hoop

Two wheels having the same radius and mass rotate at the same angular velocity. One wheel is made with spokes so nearly all the mass is at the rim. The other is a solid disk. How do their rotational kinetic energies compare?

The wheel with the spokes has about twice the KE.

You hold a piece of wood in one hand and a piece of iron in the other. Both pieces have the same volume, and you hold them fully under water at the same depth. At the moment you let go of them, which one experiences the greater buoyancy force?

They experience the same buoyancy force.

It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it it nighttime. The water is cold. The next day, you go swimming again during the hottest part of the day, and even though the air is warmer the water is still almost as cold. Why?

Water has a high specific heat.

As heat is added to water, is it possible for the temperature measured by a thermometer in the water to remain constant?

Yes, the water could be changing phase.

Which of the following possibilities could increase the efficiency of a heat engine or an internal combustion engine?

a) Increase the temperature of the hot part of the system and reduce the temperature of the exhaust. c) Decrease the temperatures of both the hot part and the exhaust part of the system by the same amount.

An object oscillates back and forth on the end of a spring. Which of the following statements ARE true at some time during the course of the motion?

a) the object can have zero velocity and, simultaneously, nonzero acceleration c) the object can have zero acceleration and, simultaneously, nonzero velocity d) the object can have nonzero velocity and nonzero acceleration simultaneously

Suppose you pull a simple pendulum to one side by an angle of 5°, let go, and measure the period of oscillation that ensues. Then you stop the oscillation, pull the pendulum to an angle of 10°, and let go. The resulting oscillation with have a period...

about the same as the period of the first oscillation

Three containers are filled with water to the same height and have the same surface area at the base, but the total weight of water is different for each. In which container does the water exert the greatest force on the bottom of the container?

all three are equal

Consider a wave traveling down a cord and the transverse motion of a small piece of the cord. Which of the following is true?

b) the frequency of the wave must be the same as the frequency of a small piece of the cord c) the amplitude of the wave must be the same as the amplitude of a small piece of the cord

At a playground, two young children are on identical swings. One child appears to be about twice as heavy as the other. If you pull them back together the same distance and release them to start them swinging, what will you notice about the oscillations of the two children?

both children swing with the same period

An ideal gas undergoes an adiabatic expansion, a process in which no heat flows into or out of the gas. As a result,

both the temperature and pressure of the gas decrease

Radiation is emitted

by any object not at 0 K

Consider a force F=80N applied to a beam. The length of the beam is l=5m, and theta=37°, so that x=3m and y=4m. Of the following expressions, which ones give the correct torque produced by the force F around point P?

c) (80N)(5m)(sin37°) e) (80N)(3m) f) (48N)(5m)

When you apply the torque equation T=0 to an object in equilibrium, the axis about which torques are calculated...

can be located anywhere

An object of mass m rests on a frictionless surface and is attached to a horizontal ideal spring with spring constant k. The system oscillates with amplitude A. The oscillation frequency of this system can be increased by...

decreasing m

An organ pipe with a fundamental frequency f is open at both ends. If one end is closed off, the fundamental frequency will

drop by half.

A wave transports...

energy but not matter

A rowboat floats in a swimming pool, and the level of the water at the edge of the pool is marked. Consider the following situations. i) The boat is removed from the water. ii) The boat in the water holds an iron anchor which is removed from the boat and placed on the shore. For each situation, the level of water will...

fall

When a baseball curves to the right, air is flowing...

faster over the right side than over the left side

Water flows in a horizontal pipe that is narrow but then widens and the speed of the water becomes less. The pressure in the water moving in the pipe is...

greater in the wide part

Bonnie sits on the outer rim of a merry-go-round, and Jill sits midway between the center and the rim. The merry-go-round makes one complete revolution every 2 seconds. Jill's linear velocity is...

half of Bonnie's

A musical note that is two octaves higher than a second note

has four times the frequency of the second note.

Do you expect an echo to return to you more quickly on a hot day or a cold day?

hot day

If there were a great migration of people towards the Earth's equator, the length of the day would...

increase because of the conservation of angular momentum

One mole of an ideal gas in a sealed rigid container is initially at a temperature of 100 degrees C. The temperature is then increased to 200 degrees C. The pressure of the gas

increases by about 25%

A student attaches one end of a Slinky to the top of a table. She holds the other end in her hand, stretches it to a length l, and then moves it back and forth to send a wave down the Slinky. If she moves her hand faster while keeping the length of the Slinky the same, how does the wavelength down the Slinky change?

it decreases

A small mass m on a string is rotating without friction in a circle. The string is shortened by pulling it through the axis of rotation without any external torque. What happens to the angular velocity of the object?

it increases

A small mass m on a string is rotating without friction in a circle. The string is shortened by pulling it through the axis of rotation without any external torque. What happens to the tangential velocity of the object?

it increases

A car speedometer that is supposed to read the linear speed of the car uses a device that actually measures the angular speed of the tires. If larger-diameter tires are mounted on the car instead, how will that affect the speedometer reading?

it will read low

A woman is balancing on a high wire which is tightly strung. The tension in the wire is...

much more than the woman's weight

A uniform beam is hinged at one end and held in a horizontal position by a cable. The tension in the cable...

must be at least half the weight of the beam, no matter what the angle of the cable

In which of the following is the wavelength of the lowest vibration mode the same as the length of the strong or tube?

none of the above are correct

When an ideal gas is warmed from 20 degrees C to 40 degrees C, the gas's temperature T that appears in the ideal gas law increased by a factor

of 1.07

Two waves are traveling toward each other along a rope. When they meet, the waves...

pass through each other

You put two ice cubes in a glass and fill the glass to the rim with water. As the ice melts, the water level...

remains the same

Two children are balanced on opposite sides of a seesaw. If one child leans inward toward the pivot point, her side will...

rise

Beaker A is filled to the brim with water. Beaker B is the same size and contains a small block of wood which floats when the beaker is filled with water to the brim. Which beaker weighs more?

same for both

A guitar string vibrates at a frequency of 330 Hz with wavelength 1.4 m. The frequency and wavelength of this sound in air reaches our ears

same frequency, shorter wave

A grandfather clock is "losing" time because its pendulum moves too slowly. Assume that the pendulum is a massive bob at the end of a string. The motion of this pendulum can be sped up by...

shortening the string

If you used 1000 J of energy to throw a ball, would it travel faster if you threw the ball (ignoring air resistance)...

so that it wasn't rotating

Suppose you are sitting on a rotating stool holding a 2- mass in each outstretched hand. If you suddenly drop the masses, your angular velocity will

stay the same

As you increase the force that you apply while pulling on a rope, which of the following is NOT affected?

the Young's modulus of the rope

Heat is

the amount of energy transferred between objects as a result of a difference in temperature

Why does an ocean liner float?

the average density of the ocean liner is less than that of seawater

Two equal-mass liquids, initially at the same temperature, are heated for the same time over the same stove. You measure the temperatures and find that one liquid has a higher temperature than the other. Which liquid has the higher specific heat?

the cooler one

A steel plate has a hole in it with a diameter of exactly 1.0 cm when the plate is at a temperature of 20 degrees C. A steel ring has an inner diameter of exactly 1.0 cm at 20 degrees C. Both the plate and the ring are heated to 100 degrees C. Which statement is true?

the hole in the plate and the opening in the ring get larger.

Two spheres have the same radius and equal mass. One sphere is solid, and the other is hollow and made of a denser material. Which one has the bigger moment of inertia about an axis through its center?

the hollow one

Two objects are made of the same material, but they have different massed and temperatures. If the objects are brought into thermal contact, which one will have the greater temperature change?

the one with the lesser mass

The temperature of an ideal gas increases. Which of the following is true?

the pressure, the volume, or both may increase.

A guitar player shortens the length of a guitar's vibrating string by pressing the string straight down onto a fret. The guitar then emits a higher-pitched note, because

the string vibrates at a higher frequency.

An ideal gas is in a sealed rigid container. The average kinetic energy of the gas molecules depends most on

the temperature of the gas

An ideal gas undergoes an isobaric compression and then an isovolumetric process that brings it back to its initial temperature. Had the gas undergone one isothermal process instead,

the work done on the gas would be greater

The rms speed of the molecules of an ideal gas

will increase as the temperature of a gas increases

In an isobaric compression of an ideal gas,

work is done on the gas

A heat engine operates between a high temperature of about 600∘C and a low temperature of about 300∘C. What is the maximum theoretical efficiency for this engine?

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