Physics

posted by .

As measured from centre ice, a single wildly cheering hockey fan can produce a sound intensity level of 60dB. What sound intensity level would be produced by
20 000 cheering fans?

---------

If sound waves travel through the ground with an average speed of 6150 m/s and a powerful explosion occurs 5.00kn away, how much time will elapse between when you feel the vibration from the explosion and hear the explosion? Use v=344m/s for the speed of sound in air.

--------

You pick up two metal rods that look the same and appear to have the same mass. However, when you strike the first rod, it produces a sound that has a much higher frequency than the second rod. What does this result tell you about the speed of sound in the two rods?

THANKS.

• Physics -

1. L = Lₒ + 10•logN = 60 +10•log(20000) =60 +10•4.3 =103 db.
2. t1 = s/v1 = 5000/6150 =0.81 s.
t2 = s/v2 = 5000/344=14.53s.
Δt =14.53 – 0.81 =13.72 s.
3. The frequency is set by the oscillating body which sets up the sound waves. The speed of the waves is determined by the elastic/inertial properties of medium and the wavelength.
λ = v/f (the higher wavelength the higher frequency)
The speed of sound doesn’t depend on frequency.

Similar Questions

1. Physics

This time I have two questions: #1.A recording engineer works in a soundproofed room that is 49.7 dB quieter than the outside. If the sound intensity in the room is 2.66 x 10-10 W/m2, what is the intensity outside?
2. physics - sound level

The source of a sound wave has a power of 2.50 µW. Assume it is a point source. (a) What is the intensity 6.70 m away?
3. Physics

The intensity due to a number of indipendent sound sources is the sum of the individual intensities. A) When four quadruplets cry simultaneously, how many decibels greater is the sound intensity level than when a single one cries?
4. physics

1.) The average sound intensity inside a busy neighborhood restaurant is 3.*10^-5 W/M^2. How much energy goes into each ear (area = 2.1 * 10^-2 m^2) during a one hour meal?
5. physics

Factory Worker A is exposed to a sound of a constant intensity of 6.30 × 10–4 W m–2 at a distance of 1.00 m from a noisy machine. The frequency of the sound is 4.00 kHz. (a) What is the sound level in decibels (dB) of this sound?
6. STUPID PHYSICS

As measured from centre ice, a single wildly cheering hockey fan can produce a sound intensity level of 60dB. What sound intensity level would be produced by 20 000 cheering fans?