Question

An unbelievably LOUD car alarm at 4:12 AM at the intersection of Jewel Avenue and 150th Street sends out a pure tone at 400 s-1. The speed of sound is 343 m/s. What frequency is heard from:

a) a car racing TOWARD it at 50 m/s (112 mph)

b) a car racing AWAY from it at 50 m/s (112 mph)

Answer #1

Part A.

When observer is moving towards stationary source, then Using Doppler's effect

f1 = f0*(V + Vo)/V

Vo = Speed of observer = 50 m/sec

f0 = Original frequency = 400 s^-1 = 400 Hz

V = Speed of sound = 343 m/sec

So, observed frequency will be

f1 = 400*(343 + 50)/343

**f1 = 458.3 Hz**

B.

When observer is moving away from stationary source, then Using Doppler's effect

f2 = f0*(V - Vo)/V

Vo = Speed of observer = 50 m/sec

So,

f2 = 400*(343 - 50)/343

**f2 = 341.7 Hz**

**Please Upvote.**

The security alarm on a parked car goes off and produces a
frequency of 758 Hz. The speed of sound is 343 m/s. As you drive
toward this parked car, pass it, and drive away, you observe the
frequency to change by 68.5 Hz. At what speed are you driving?

The security alarm on a parked car goes off and produces a
frequency of 1370 Hz. The speed of sound is 343 m/s. As you drive
toward this parked car, pass it, and drive away, you observe the
frequency to change by 147 Hz. At what speed are you driving?

Please show all your work.
A source of sound is located in a room a distance “L” from a
wall. The room temperature is 72°F. AN observer is located between
the source and the wall at 103 cm from the wall. The observer can
hear a loud sound at the 3rd harmonic and the sound
fades at the 4th harmonic.
What is the velocity of sound in the room?
What is the frequency at which the observer can hear the...

A stone is dropped from the top of a cliff. The splash it makes
when striking the water below is heard 3.2 s later. How high is the
cliff?
2. The pressure variation is a sound wave is given by Δ P =
0.0035 sin (0.38 π x – 1350 π t) Determine a. the wavelength b. the
frequency c. the speed and d. the displacement amplitude of the
wave. Assume the density of the medium to be 2.2 x...

11. A simple pendulum undergoes small-angle oscillations. Which
of the following pairs (mass, string length) will oscillate with a
period greater than 2.2 seconds?
a) (0.50 kg, 1.0 m)
b) (0.40 kg, 0.80 m)
c) (1.0 kg, 0.50 m)
d) (0.80 kg, 0.40 m)
e) none of the above answers are correct
(numbers 15-17) An ideal horizontal spring-mass system begins
oscillation with the mass at x=0 (the spring is relaxed) and moving
in the -x direction at 6.00 m/s. The...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 54 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago