SOUND WAVES

A jackhammer is causing vibrations in a wall that is connected to the concrete being jackhammered. When the hammer is stopped, the wall ceases to vibrate. This type of vibration is: resonance forced vibration an example of beats none of the above

forced vibration

Some equipment that was in operation caused continuous amplification of vibrations in a structure being worked on. This type of vibration is: resonance forced vibration an example of beats none of the above

resonance

How long would it take for a sound impulse to travel through an aluminum rod 150 meters long? _____ s 34 0.029 0.29 3.4

0.029

How long would it take for a sound impulse to travel through a copper rod 2.0 km long? _____ s 1.75 0.057 0.57 17.5

0.57

If a train is 100 km away, how much sooner would you hear the train coming by listening to the rails (iron) as opposed to listening for it standing by the track? In other words, how much faster will the sound travel through the iron rails than through the air? Assume the air temperature is 0°C. Sound will reach you ___ seconds sooner.

280.

Find the speed of sound in air that is 30.0°C. ___ m/s

350.

Match the following vocabulary words. Match the items in the left column to the items in the right column. 1.the vibration of an object as its natural frequency caused by a force or wave of the same frequency 2.a series of alternating reinforcements and cancellations produced by the interference of waves 3.the cone-shaped wave made by a particle moving faster than the speed of a wave in that medium 4.the apparent change in frequency perceived when the source and observer are approaching

3 shock wave 2 beats 4 shock wave 1 resonance

A train traveling 80.0 kph is blowing its horn as it approaches a railroad crossing. The horn has a frequency of 300.0 Hz. Assume the speed of sound is 331.5 m/s. What is the observed frequency of the horn? ___ Hz

322

A truck is traveling 70.0 kph away from you. The driver is blowing the horn, which has a frequency of 400 Hz. The air temperature is 25°C. What is the observed frequency of the horn? _____ Hz 424 379 330. 333

379

When a 480 Hz. tuning fork and a piano key are struck together, four beats are heard. When a 470 Hz. tuning fork and the same piano key are struck, six beats are heard. What is the frequency of the piano key? unknown piano key = ________ Hz 476 478 477 475

476

Two tuning forks, 254 Hz. and 260 Hz., are struck simultaneously. How many beats will be heard? ___ beats/s

6.00

A car approaches you with its horn blowing. The observed frequency is 503.7 Hz. Assume the speed of sound is 1100 ft/s. The car's horn has a frequency of 450 Hz. How fast is the car going? Express your answer in mph. ___ mph

79.8

Determine the difference in the speed of sound in hydrogen at 0°C and in air at 30°C. Also indicate if it is faster or slower. ___ m/s ___ than in air.

934 faster

Resonance always causes the object resonating to fall apart or be destroyed. True False

False