Physics Exam #3

A flute and a piccolo are both effectively pipes that are open at both ends, with holes in their sides to allow them to produce more tones. The piccolo is very nearly a half-size version of the flute. How does this fact explain why the piccolo's tones are one octave above those of a flute?

Because the air column inside a piccolo is half the length of the air column inside a flute, it vibrates at twice the pitch of the air column inside a flute.

How are standing waves and traveling waves similar?

Both waves involve oscillation of some medium

What two properties of a material affect the speed of sound in the material?

Density and stiffness

What happens to the amplitude of a system at resonance?

It increases

The frequency of a sound wave doubles. What happens to the wave speed?

It is unchanged

What does the period of a pendulum depend on

Length and gravity

Gravity creates

Pressure gradients in fluids

What is the best definition of resonance?

The frequency at which an object vibrates with maximum amplitude

Which of the following conditions is necessary for resonance to occur?

The frequency of the driving force is equal to the natural frequency of the system

Cities have to use water towers to supply water to because

Water pressure at the bottom of the tower is much higher than at the top

Suppose you had a very long straw that could reach from a cup of water on the ground level to the top of a very tall building. When you suck on the straw in order to bring water up

You could bring the water up to only a certain height in the straw because the atmosphere pushes down on the surface of the water by a given amount

The reason for using a harmonic oscillator as a clock's time-keeper is so that the clock will keep accurate time even if the

amplitude of the time-keeper's oscillation changes

If you blow across the top of a half full bottle of soda, you can produce a clear tone. If you take a drink of soda to reduce the amount of liquid in the bottle and try this again the pitch (frequency) of the sound produced will

decrease

As they Reynold's number increases

flow is going from being viscous dominated to inertia dominated and therefore turbulent

Flowing honey is less likely to become turbulent than flowing water becuase

honey's large viscosity favors laminar flow

You have just set up a weather station for your daughter to observe wind speeds at home. You had to move it up from the ground because when it was too close to the ground the wind speed readings are all too small. This is because

the boundary layer of a moving fluid moves slower than at other points farther into the fluid

The pressure in a water pipe is always lower in regions where the water moves faster only when

the pipe is level

They place their thumb over the end of the hose, and the water squirts out very quickly, because their thumb increases

the pressure of the water in the hose

The waves produced by plucking a guitar string are

transverse

The reason fast-moving water makes noise is

turbulence

A squirt gun is a simple type of water pump in which a plunger attached to the trigger forces water out of a nozzle and across the room. When you squeeze the trigger of the gun, water squirts out of the nozzle because

The pressure inside the gun is higher than the atmospheric pressure

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 a gas lighter than air and then blow gently across the top of the bottle, it will emit

a higher pitched tone

The strings of a guitar vibrate at different frequencies. They have different thicknesses because

a thicker, more massive string vibrates at a lower frequency than a thinner string of the same length and tension

A guitar string that normally vibrates with a fundamental frequency of 110 Hz is also capable of vibrating at 330 Hz. When that higher frequency vibration occurs, the string is vibrating

as 3 strings that are one third as long as the overall string

On a warm, balmy summer day, you decide to relax by watching the latest building renovation in your neighborhood. You notice that a very heavy wrecking ball is attached to a much lighter chain and is dangling from a crane and swinging back and forth. As long as it does not swing too high the time it takes the wrecking ball to complete one full oscillation will be independent of

both the amplitude of the motion and the weight of the ball

You decide to take your younger brother to the park for a fun afternoon. You notice that one ride is basically a seat attached to an old car spring. When a person sits on it, the spring vibrates rapidly but when in a car the spring vibrates much more slowly. This is because

larger masses on a spring give lower frequencies

To improve a xylophone's appearance, the orchestra director decides to have it painted. Each xylophone bar is actually a harmonic oscillator that vibrates when struck by a wooden mallet. When bending in its fundamental mode, the bar's middle and ends move in opposite directions. Painting the bar adds mass to the bar without affecting its stiffness, so the paint will

lower the bar's pitch

You are a superb proposal writer and convince NASA to fund your taking a pendulum clock to Mars and study how it runs. Compared to the time it should keep on Earth, the clock will run

slower

You decide to attend an amusement park which has a ride where you are strapped into a chair which is in turn firmly attached to a plastic cable. You are released and you bounce up and down as a harmonic oscillator-a mass on the end of spring. Next in line is somebody who weights twice as much as you do. When the heavier person goes on the ride, you notice that

the heavier rider will have a longer period than the lighter one

When you get new tires installed on your car the wheels are carefully balanced by placing small weights around the outside of the rim. If one of these weights falls off, your car may vibrate violently when you drive at certain speeds. This vibration occurs for speeds at which

the rotation frequency of the off-balance wheel matches the frequency at which the car's suspension vibrates, allowing a resonant energy transfer between the two

A harmonic oscillator is an oscillator

with a restoring force proportional to its displacement from equilibrium