Acoustics Answers

A sound pulse ( like a loud clap ) is directed toward the wall of a tall building that is 680 m from the source of the sound. The reflected wave is detected 4.0 seconds after the pulse is produced.

A) how long does it take the pulse to reach the building?
B) what is the speed of the sound pulse?

Given that the maximum force your forehead can take is about 6000N, while the maximum
force your cheekbone can take is 1300N. If a 0.14 kg solid ball strikes any part of your head at
39 m/s and stops in 1.2 × 10−3 s, which of the following is correct:
a) Only your forehead will be in danger of fraction.
b) Nor your forehead neither your cheekbone will be in danger of fraction
c) Only your cheekbone will be in danger of fraction.
d) Both your forehead and your cheekbone will be in danger of fraction
e) I cannot decide because the mass of the head is not known

what is density

What do you understand by wave impedance? Derive an expression for the
impedance offered to sound waves propagating in a gaseous medium.

For a metal rod, the value of Young’s modulus is 1.5X10^11 Nm^-2 and density is 7500 kgm^-3
Calculate the speed of sound in the metal rod.

Calculate the fundamental frequencies and the first 3 overtones of a pipe of length 1.7 m
and closed at one end.

Speed of a wave having frequency 300 Hz is 340 m/s. Find out its wavelength.

A monkey in a perch 20 m high in a tree drops a coconut above the head of a zoo keeper as he runs with a speed1.5 m/s beneath the tree actually intending to hit the toes of the zoo keeper,how early in seconds should the coconut be dropped by the monkey

An electric kettle contains 1.5 kg of water at
100o
C and powered by a 2.0 kW electric element. If the thermostat of the kettle fails to operate, approximately how long will it take for the kettle boil dry? (Take the specific latent heat of vaporization of water as
2000kJkg−1)

One of these is an example of thermal radiation detector
bolometer
thermometer
thermal rod
thermal glass