While decorating your new guitar, you accidently coat one of the guitar strings with spray paint. That paint increases the string's mass. How will that change affect the string?

Even though your Thanksgiving dinner consists of a tofu turkey, you discover that it contains a wishbone. You and your cousin decide to break the wishbone; the one with the large half gets their wish. Your cousin holds one end of the wishbone motionless as you pull the other end toward you rapidly. The wishbone snaps and you're left holding only a tiny fragment. Better luck next time! Breaking the wishbone required energy and that energy was provided by

After clearing the bar in the high jump, you land softly on a giant mattress. Landing on the mattress is much more comfortable than landing on a sand heap of equal size because

Because of bad planning during the design and construction of a high-rise apartment building, all 50 floors of the building receive their water from a single pipe. That pipe is fed from a water tank located on the building's roof. On opening day, residents on various floors begin taking showers and have different experiences. They quickly discover that the total energy per liter in the spraying water is (neglecting any effects of viscosity and friction)

What change can you make to a pendulum to increase its period of oscillation—that is, the time it takes to complete one full cycle of oscillation?

Two cans of soup, one of which weighs twice as much as the other, roll off of a horizontal table together at the same initial velocity. In this situation,

Firefighters are battling a fire on the 10th floor of an apartment building. When they stand on the ground, water flowing through their firehose from their firetruck can only shoot the water up to the 8th floor. So they carry the end of the same fire hose up a 2-story-tall ladder and again start shooting water upward. Now the water rises to the

Winds are powered by temperature differences at the Earth's surface. As those temperature differences grow larger with climate change, the winds may also grow stronger. Why are larger temperature difference capable of producing stronger winds?

When the A-string of a guitar vibrates in its fundamental mode without anyone touching it, it has a frequency (or pitch) of 110 cycles per second. When that same string is vibrating at 330 cycles per second without anyone touching it, it is vibrating in its

An airplane is cruising at constant velocity, 30,000 feet in the air. Which of the following correctly describes the situation above the airplane's wing?

The maximum speed of a rocket-propelled spaceship with an exhaust speed of 5000 mph is

During the power stroke in one cylinder of a car's engine, the burned fuel and air push the piston out of the cylinder. In accordance with Newton's third law, the piston pushes back on the burned gas. Overall, the

On a humid summer day, perspiration doesn't cool you off much because

You drop a cylindrical can of soup and its flat bottom lands hard on the cement floor. As the result of the liquid-filled can's violent impact with the floor, its sides bulge outward. The bulge(s) is/are located at the

While most western musical instruments are based on harmonic oscillators, there are some instruments that are not harmonic oscillators. What feature of an instrument's sound would indicate that it is not a harmonic oscillator?

Why must a sprinter lean forward as she picks up speed at the start of a race?

Your French fries are getting cold as you wait for your server to bring you a new bottle of ketchup. In frustration, you decide to get the last bits of ketchup out of the old bottle by swinging it rapidly in a circle with the cap-end of the bottle pointing away from you. This technique works because

It is a beautiful summer day and the residents of a high-rise apartment building are eating dinner on their balconies. A resident accidentally knocks an empty glass off a balcony that is about 80 meters (260 feet) above the cement patio. The glass would have smashed on that patio after falling for 4 seconds, however, a quick-witted resident catches the glass after it has fallen for only 2 seconds. How far above the patio was the glass when it was caught?

You drop an extremely bouncy rubber ball on a cement floor and it rebounds upward almost to its original height. Compare the ball's energy and momentum just before it bounced on the floor with its energy and momentum just after bounced off the floor.

When the cylinder in an automobile's engine is going through the compression stroke, the piston squeezes the fuel and air mixture into a smaller volume within the cylinder. As the piston moves into the cylinder, the piston does work on the fuel and air mixture and

When water rushing through a hose flows around a bend in that hose, its pressure changes. The water pressure

When you light a candle, its flame turns wax molecules and oxygen into water and carbon dioxide molecules. The molecules that form during this combustion have

Since a water molecule weighs less than the average air molecule, humid air is less dense than dry air. Suppose that the humidity of the air increases significantly during an orchestra concert. How will the resulting decrease in air density affect the wind instruments (e.g., flutes, clarinets, oboes)?

One warm spring day you and some friends go to the beach at a nearby lake. The beach ball you are playing with is not quite fully inflated, so the pressure inside it is atmospheric. Someone accidentally knocks the ball into the lake. Although it is a very hot day, the water is very cold and nobody wants to retrieve the ball. You notice that the ball seems to have deflated somewhat after sitting in the water for a while. The contact with the cool water has caused the temperature of the air inside the ball to drop, resulting in a significant

An automobile engine "knocks" when the gas in its cylinder ignites spontaneously rather than waiting for the sparkplug to ignite it. During which of the 4 strokes can this premature ignition occur?

When you pull a pendulum away from equilibrium and let go, the pendulum swings back and forth rhythmically for a very long time. What physical quantity keeps it going for so long?

If a golf ball were smooth rather than dimpled, it would

You are inflating a shiny plastic balloon with helium. The balloon starts as a thin, flat bag but it gradually gets thicker as it fills. At first, the thin plastic balloon doesn't float. But as you keep adding helium to the balloon and it gets thicker, it eventually begins floating because

A typical heat pump (an air conditioner run backwards so that it heats the indoor air) consumes 2000 watts of electric power. How much thermal power does it provide to the indoor air?

You are drying your hair and you have put a diffuser (an anti-nozzle) on the end of the dryer. As it goes through the diffuser, the air slows down and its

Your winter jacket contains 8 ounces of goose down insulation, just enough to completely fill the interior of the jacket. Suppose you open the seams and tightly pack 8 more ounces of goose down insulation into the jacket without changing its dimensions at all. After sewing up the seams, your jacket will be

An air conditioner's compressor takes low density gas and compresses that gas to high density and that gas begins to condense into a liquid. Why does compressing the gas cause it to condense?

Your coffee has cooled off and you decide to heat it the hard way: you stir the coffee vigorously for 10 minutes. The coffee does become slightly hotter. What causes this rise in temperature?

In its fundamental vibrational mode, a guitar string vibrates as a single string. In its second harmonic mode, the string vibrates as two half-strings. How do those two vibrations differ?

You are flying a kite on a long string and the kite hovers motionless in the sky as the wind blows past it. The kite is high up to your east and you are pulling the kite string downward and westward. In which direction is the kite pushing on the air that passes it?

A metal ball hanging from a coil spring can bounce up and down as a harmonic oscillator. Which of the following changes will increase the ball's period—that is, the time it takes the ball to complete one full cycle of its bouncing motion?

If you try to cook vegetables with 100 °C air, it takes a long time. But if you cook those same vegetables with 100 °C steam, they cook quickly. This is because the steam

You watch from the ground as a crane lifts a large bucket of cement upward to a construction project. The bucket and cement are moving straight upward at constant velocity. As the crane's cable lifts the bucket, the cable is

Running on soft dry sand is exhausting, so you switch to running on hard wet sand. The hard wet sand removes less energy from you because it

You remove a plastic container and its lid from the hot dishwasher. After snapping the lid on the container, you put the sealed container of air on the counter to cool. When you examine the container later, you find that its lid has bowed inward significantly, reducing the container's volume. How has the cooling process affected the air pressure and air density in the container?

You are visiting a playground and you notice that a girl on one swing completes each full cycle of motion in much less time than a boy on another swing. The girl has a much shorter period of motion (time between cycles) than the boy because

Your new dorm room is too hot in the summer, so you decide to install a window air conditioning unit. Since your room has no window, you install the air conditioner between your room and a suitemate's room. When you plug it in and turn it on, the unit transfers heat from your room to your suitemate's room and your room becomes pleasantly cool. As the unit does its job, what is happening to entropy?

Water is flowing through a horizontal pipe in laminar, steady-state flow. Halfway along the pipe, its diameter decreases and the water must continue on through that narrow second half. Compared to when it was in the wide first half of the pipe, water in the narrow second half of the pipe is moving

You add a teaspoon of salt to a glass of pure water. The salt initially sits at the bottom of the water, but it slowly dissolves so that eventually you have a glass of salt water. Which has more entropy: the glass of pure water with salt sitting at its bottom or the glass of salt water?

A tall flagpole is topped by a metal ball. When a large bird leaps off the ball, the flagpole starts bending back and forth rhythmically about its straight equilibrium shape. At what moment(s) during its rhythmic motion is the ball moving fastest?

If you're designing an energy efficient automobile, why should you minimize the diameter of the turbulent wake it leaves behind in the air?

The three nonflammable objects in your hand are identical except that one is black, one is white, and one is shiny. You place them in a roaring fire and soon they have the same temperature: 1800 °C. They remain solid. Which one is glowing most brightly?

You are driving Northward on a highway when you come to a smooth 90° turn toward the right. You maintain a constant speed around the turn and are soon driving Eastward. During the middle of the turn, in which direction were you accelerating?

If you strike a stiff, spring-like surface with a mallet and listen to the sound it emits, you'll notice that this sound is more complicated than that emitted by a string or a thin bar. That's because surfaces

Two photographs show the same thermally isolated room containing the same air molecules, water molecules, and ceramic mug. In one photograph, the air is moist and the mug is empty. In the other photograph, the air is dry and the mug contains liquid water. Of these two photographs, the situation in which the air is moist and the mug is empty has

When you pour milk from a pitcher into a bowl, the flow is likely to become turbulent. When you pour honey from a jar into a bowl, however, the flow is likely to remain laminar. Compared to milk, honey is more likely to exhibit laminar flow because honey's larger

The hotter it is outside, the more electric energy an air conditioner must use to remove each joule of heat from the 72 °F indoor air in your home. It must consume more electric energy on a hotter day because

Your bottle of oil and vinegar salad dressing has separated, so that the oil is floating on the vinegar. You notice that a large herb is floating motionless at the interface between the oil and the vinegar. That herb's average density is

A seemingly "haunted" house emits creaking sounds as it cools off at night. Since sound carries energy, the house must obtain that energy from somewhere (other than ghosts and goblins). While this energy begins as thermal energy, the sound doesn't appear until the outside temperature drops well below the temperature of the house because

A satellite is orbiting the earth in a not-quite-circular orbit. As it moves, the satellite is accelerating

Increasing the amount of carbon dioxide (a greenhouse gas) in the earth's atmosphere

You are cleaning the siding on your house by spraying water at it from a hose and nozzle. At the center of the stream of water, right where it hits the siding, the water is coming to a complete stop. The pressure in the water at the center of the stream as it touches the siding is

A bottle in both thermal and phase equilibrium at 0 °C contains 1 kilogram of ice and 1 kilogram of liquid water. You move the bottle to a new location and allow it to reach equilibrium at 0.5 °C. The bottle now contains

If you pluck a guitar string at different points along its length, it will produce somewhat different sounds. What is different about the string when you pluck it at different points?

You are standing in the middle of a level subway car that is moving forward at constant velocity when another passenger accidentally spills an enormous container of olive oil. Suddenly, the floor cannot exert any frictional forces on your feet. Because nothing else is touching you, you