You're the first person to visit Mars and you've just met a group of Martian schoolchildren. They are playing street hockey with parts from the Mars Polar Lander and, after years of watching Star Trek reruns, they are fluent in English. One of them asks you how your weight and mass have changed since you left Earth. You take a moment to measure both and reply correctly that

A friend has purchased an old pendulum clock at a yard sale. Its pendulum is discolored, so your friend applies a thick layer of brass-colored spray paint. That paint increases the pendulum's mass and its weight. How does painting the pendulum affect the pendulum's period? [Ignore effects due to the air and other insignificant influences.]

Increasing the tension in a guitar string

You are enjoying an elegant candlelit dinner for two but the waiter has been a little careless with the ice. Your glass of ice water contains 25% water and 75% ice, while your friend's glass contains 75% water and 25% ice. The temperature of your glass of ice water

Why does a paper cup of hot coffee cool so much more slowly if you cover it with a thin plastic lid?

As you knead bread dough, squeezing it and folding it repeatedly, the dough becomes hotter. What causes this rise in temperature? [Neglect any heat that flows between your hands and the dough due to differences in their temperatures.]

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

Water flows gently from a kitchen faucet. You block most of the faucet's opening with your thumb and now the water sprays out at high speed because you

How is a steam engine able to obtain work (ordered energy) from hot steam?

As the temperature difference between indoor air and outdoor air decreases, the electric energy an air conditioner consumes as it moves one joule of heat also decreases. Why?

A birdfeeder hangs from a tree-branch on a long string and it can swing back and forth like a pendulum. As its birdseed is consumed, the birdfeeder's mass decreases and its center of mass moves downward. How do these two changes affect the period of the birdfeeder's swinging motion?

You are a patent examiner for the government and the invention you are examining claims to convert heat continuously into electric power. According to the inventor, when you put this device in the middle of a room and turn it on, it gradually cools the room air while providing a steady and endless supply of electric power. You wisely reject this patent application because, in order to work as described, it would have to have to

A common type of water pump produces pressurized water by spinning a cylindrical volume of water rapidly about its center. Water enters the pump where the water pressure is smallest and leaves the pump where the water pressure is greatest. Where on the cylinder of water does the water enter and leave the pump?

At the cruising altitude of a commercial jet plane, the air's density is too low to support life. The plane must therefore compress the outside air before sending it into the pressurized cabin. After compressing the air, the plane must send that air through an air conditioner because the act of compressing that air

To win a stuffed animal at the state fair, you simply need to drop a glass marble onto a stationary glass plate and have the marble come to rest on that plate. Unfortunately, when the marble hits the plate, it bounces upward because the marble

You fill a rubber balloon with water and use your hand to throw the balloon forward horizontally. As the balloon accelerates forward rapidly, where in the balloon is water pressure greatest?

Someone props open the door to your jazz club on a cold winter evening and the air temperature in the club decreases dramatically. The air pressure remains unchanged. How does this decrease in air temperature affect the sound of the Saxaphone (a wind instrument)?

You seal a leftover sprig of parsley in a large zippered plastic bag and put them in the refrigerator. There was a substantial volume of air trapped in the bag, but the air's volume decreases as the refrigerator cools the bag. The decrease in the bag's temperature caused

Liquid water can coexist with ice at 0 °C. If you dissolve sugar in the water, it

As heat flows from a hot woodstove to a cold room, the entropy of the woodstove

You are riding a roller coaster and your speed is increasing as you plunge downhill on the first hill. Your acceleration is directed

A gold flute produces a tone as the flautist blows across a hole near the end of the flute. What is vibrating to produce this tone?

During your ride in a hot air balloon, the pilot turns on the flame to heat up the air inside the balloon's envelope (the balloon's fabric skin). That envelope is open at the bottom, where the flame heats it. As the temperature of the air inside the unsealed envelope increases,

During its compression stroke, a car-engine's piston squeezes the fuel and air mixture into a smaller volume within a cylinder. As the piston moves into the cylinder, the piston does work on the gas and the

After John Glenn completed 3 orbits of the Earth in May 1961, it was time to return his spaceship to the ground. In which direction did rocket engines push his spaceship to cause it to descend into the atmosphere for reentry?

Firefighters are battling a fire on the 12th floor of an apartment building. When they stand on the ground, their fire hose can only shoot the steady stream of water up to the 10th floor. So they carry the end of the same fire hose up a 2-story-tall ladder and shoot water upward. The other end of the hose remains attached to the same water source as before. Now the steady stream of water rises to the

As a soccer ball moves swiftly through the air, it experiences pressure drag because the air pressure

An electric space heater is perfectly efficient: it consumes 1500 watts of electric power and provides 1500 watts of thermal power to the indoor air. In comparison, a heat pump (an air conditioner run backwards so that it heats the indoor air) that consumes 1500 watts of electric power provides

When a log is floating on water, much of the log is above the water and is actually surrounded by air. If that surrounding air were to disappear suddenly, the log would

You purchase an antique balance-ring clock. When you place the clock upright on your dresser, it keeps perfect time. A friend tips the clock gently onto its back, so that its face and hands are visible from above instead of from the side. How does this change in orientation affect the clock?

A space tourism company offers to carry people to orbit in a luxurious spaceship. To perform that task, the ship's rocket engines must lift the ship above Earth's atmosphere and

The elevator in a fancy hotel has table in it and there is a vase of flowers on that table. As the elevator rises at constant velocity toward the penthouse suite, the table is

If you blow across the top of a half-full bottle of water, you can produce a clear tone. If you drink some of the water and try this again, the frequency of the sound produced will

You are pushing a shopping cart up a ramp. Both you and the cart are moving at constant velocity. The net force on the shopping cart is

As spacecraft travels from Earth to Mars, it is exposed to full sunlight continuously for about six months. Since nothing is touching that spacecraft, why doesn't the spacecraft continue to get hotter and hotter?

You are on the outdoor deck of a restaurant, watching athletes compete in winter sports. The weather is cold, but the red-hot heating element positioned about 10 feet above you keeps you surprisingly warm. Heat from that element reaches you

You and your friend are riding a carousel. Your horses are side-by-side and your friend is closer to the center of the carousel than you are. As the carousel turns steadily, which of the following is true?

As a window air conditioner cools the air in your room on a hot summer day, which of the following statements about energy and entropy is correct?

You put a metal pot of water on the stove at sea level and begin heating the water. When the water's temperature reaches 100 °C (212 °F), the water begins to boil. As heat continues to flow into the boiling water,

After drinking all the water in your plastic water bottle, you seal the bottle closed and place it in the hot sun. A while later, you find that the bottle's sides are bent slightly outward so that it has slightly more volume than before. Since you sealed the bottle, the air pressure inside the bottle has

A weather balloon is used to study the atmosphere as it float upward. The balloons starts as an empty rubber bag, but adding helium to it gradually inflates the balloon until it is many feet in diameter. At first, the balloon doesn't float. As you keep adding helium to it and it grows larger, however, it eventually begins floating because

An artist constructs a minimalist violin that has no wooden body at all. Instead, the violin's four strings are mounted on a thin streel rod. In fact, that is the entire violin! The strings are under tension and vibrate properly, but you can barely hear their sound. Why is this minimalist violin so quiet?

You have a large block of slippery ice in the back of your pickup truck. As the truck turns toward the left at high speed, the block of ice slides up against the right side of the truck bed. What force, if any, is pushing the ice toward the right?

Water is flowing smoothly through horizontal plumbing. As the water move through a bend in that pipe, compare the water on the inside of the bend to water on the outside of the bend.

It's a warm summer day and you're having lunch outdoors on a patio. A window air conditioning unit hums quietly nearby as it cools an office inside the building. Your friend notices that the unit's outdoor part is emitting a considerable amount of heat and comments on how strange that is. You explain correctly that the air conditioner's outside part is emitting the heat

When smokejumpers parachute into forest fires, they have with them emergency tents made of shiny aluminum foil. If they're caught in the blaze, they lie flat on the dirt in a low spot with the aluminum tent propped just above them. If the fire passes quickly enough, they have a good chance of surviving it. The tent is made of aluminum because

You are designing clothing and equipment that will help a downhill ski racer to win her races. Why should you minimize the size of the turbulent wake the skier produces in the air behind her?

The air that flows over the wing of an airplane in flight bends downward, toward the top surface of the wing. Compared to its speed and pressure before it encountered the wing, the air flowing just above the wing's top surface has a

Mike and Johnny are in trouble for scuffling in the school cafeteria. While Mike admits that he pushed Johnny, who immediately fell over backward, Mike claims that Johnny pushed back and is thus just as guilty. From the perspective of physics,

When the A-string of a violin vibrates in its fundamental mode without anyone touching it, it has a frequency (or pitch) of 440 cycles per second. When that same string is vibrating at 880 cycles per second without anyone touching it, it is vibrating in its

Two steel balls, one of which weighs twice as much as the other, roll off a horizontal table with the same speeds. In this situation,

A child is riding on a playground merry-go-round (a horizontal platform that rotates about a fixed center). As the merry-go-round rotates at a steady rate, the net force on the child points directly

You can put your hand in a 400 °F (200 °C) oven briefly without getting burned. However, even a second or two of contact with 212 °F (100 °C) steam can be quite painful. The steam delivers heat much faster to your hand because steam

A child is using a crayon (a stick of colored wax) to draw a picture on a sheet of paper. The paper rests on a horizontal tabletop and the child's crayon is moving across the paper at a steady speed in a straight line. Which of the following statements about the forces acting on the crayon is correct?

When a wax candle burns in air, the water and carbon dioxide molecules that form as the result of combustion reactions have

When you blow gently across the top of a particular soda bottle, it emits a tone. The column of air in the bottle is vibrating up and down in its fundamental mode. If you replace the air in the bottle with helium and then blow gently across the top of the bottle, it will emit

A sculptor is working with three non-flammable materials: a silvery metal, a black ceramic, and a white ceramic. When the sculptor heats these three materials to 1800 °C, they all begin to glow with visible thermal radiation. Which material glows most brightly?

You have two cups in front of you, one filled with water and the other filled with honey. Honey has a much greater viscosity than water. Honey has a slightly greater density than water. If you stir both liquids at equal speeds using identical spoons, which liquid is more likely to become turbulent and why?

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?

Most clocks use harmonic oscillators as timekeepers because of what important characteristic of a harmonic oscillator?