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AP Physics Daily Problem #81
Read chapter 12 (Giancoli) or section 11.10 (Hecht) before attempting this problem.
A piece of pipe, 2.0m long and open at both ends, is subjected to sound waves of all audible frequencies (white noise). What is the fundamental frequency at which the pipe will resonate. Assume that the speed of sound is 343m/s
What are the next two audible resonant frequencies of this same pipe?
AP Physics Daily Problem #82
Your ear is close to one rail of a long length of continuous welded steel railroad track. 500m away someone strikes the rail with a hammer. You will hear this event twice, once through the rail and once through the air. The speed of sound in steel is 6000m/s
How long will it take for the sound to reach your ear via the air?
How long will it take for the sound to reach your ear via the rail?
What is the time interval between hearing the two distinct sounds?
AP Physics Daily Problem #83
A hollow metal post 5.0cm in diameter is open at the top. It is set in concrete at its base. When the wind blows, a tone of 86Hz is heard.
How tall is the post?
What other harmonic tones might be heard along with the 86Hz tone?
After a strong rainstorm, the tone changes to 95Hz. Can you estimate the amount of rain that fell (in cm)?
AP Physics Daily Problem #84
A pipe has two successive audible overtones of 48 and 80Hz.
What is the fundamental frequency of the pipe?
Is the pipe open or closed?
What is the length of the pipe? Assume Vsound =343m/s
AP Physics Daily Problem #85
A police car is traveling toward you at 25m/s with its siren on. The siren puts out a tone of 1000Hz. What is the frequency of the tone you hear?
A stationary police car now starts its siren, also at 1000Hz. What is the beat frequency you would hear due to the combination of this car and the car in the previous part?AP Physics Daily Problem #86
You are tuning a piano string with a 256Hz tuning fork. You sound the string and the fork at the same time and hear the tone get louder and softer about twice per second.
What are the possible frequencies of the string?
You tighten the string slightly and the tone now gets louder and softer at the slightly increased speed of three times per second. The rate did not slow down during the tightening process. What is the frequency of the string?
If you had only tuning forks of 254Hz and 246Hz, could you tune a string accurately to 250Hz? Describe how you would do so.
AP Physics Daily Problem #87
An airplane flying at Mach 3 flies directly over an observer at an altitude of 10,000m above the ground
What is the angle of the shock wave relative to the horizontal? (hint: make a diagram!)
How far away (measured along the ground) will the airplane be when the observer first hears the airplane?
AP Physics Daily Problem #87a
You observe an airplane flying rapidly overhead and then directly away from you. You cannot hear it, so you assume that it is supersonic and flying at constant altitude.
You continue to observe the airplane and when it is exactly 25 degrees above the horizon you hear its sonic boom.
Draw a diagram illustrating this situation:
Calculate the mach number of the airplane. Assume that the speed of sound is a constant.
AP Physics Daily Problem #88
A straight stretch of railroad track 1.0km long. The rails are made of steel. The rails are laid at a temperature of 10C and the temperature at the location varies between
–10C and 45C in winter and summer.
If the lengths of rail are each 20m long, how big must the expansion gaps be?
How large will the gaps be on the coldest winter day?
AP Physics Daily Problem #89
50g of ice at 0.0C are placed in an insulated container of negligible thermal mass. 500ml of water at 90C is added to the container.
How much heat is required to melt the ice?
What is the equilibrium temperature and composition of the mixture?
AP Physics Daily Problem #89a
At room temperature, 20C, you have a steel shaft of diameter 50.00mm. You also have an aluminum hub with a hole of diameter 49.90 mm. The object is to put the shaft into the hub without forcing it.
If you decide to change the temperature of the shaft, what must the change be to allow the parts to fit?
If you decide to change the temperature of the hub, what must the change be to allow the parts to fit without forcing?
AP Physics Daily Problem #90
100 grams of ice at 0.0C and 100g of steam at 100C are combined in an insulated container. What is the final temperature and composition of the mixture? If there is more than one phase present, determine how much of each phase is present.
AP Physics Daily Problem #90a
You have 0.1 moles of a gas at standard temperature and pressure.
1. Define Standard Temperature and Pressure.
2. What is the volume of the gas at STP?
3. The gas is warmed to 100C at constant pressure, what is the volume now?
4. The pressure is then increased to 300kPa (absolute). What is the volume now?