Two-Source Interference of Sound: Two loudspeakers placed 6.00 m apart are driven in phase by an audio oscillator having a frequency range from 1908 Hz to 2471 Hz. A point P is located 4.70 m from one loudspeaker and 3.60 m from the other speaker. At what frequency of the oscillator does the sound reaching point P interfere constructively? The speed of sound is 344 m/s.
A. 2190 Hz
B. 2420 Hz
C. 2110 Hz
D. 2340 Hz
E. 2270 Hz
Answer: A
You might also like to view...
Water is heated by hot air in a heat exchanger. The flow rate of the water is 12 kg/s and that of the air is 2 kg/s. The water enters at 40°C and the air enters at 460°C. The overall heat transfer coefficient of the heat exchanger is 275 W/(m2 K) based on a surface area of 14 m2. Determine the effectiveness of the heat exchanger if it is (a) parallel-flow type or(b) a cross-flow type (both fluids unmixed). Then calculate the heat transfer rate for the two types of heat exchangers described and the outlet temperatures of the hot and cold fluids for the conditions given.
GIVEN
• Water heated by air in a heat exchanger
• Water flow rate m w= 12 kg/s
• Air flow rate m a= 2 kg/s
• Inlet temperatures
? Water (Tw,in) = 40°C
? Air (Ta,in) = 460°C
• Overall heat transfer coefficient (U) = 275 W/(m2 K)
• Transfer area (A) = 14 m2
FIND
(a) The effectiveness (e)
(b) The heat transfer rate (q)
(c) The outlet temperature (Tw,out, Ta,out) for: 1. parallel-flow 2. cross-flow
ASSUMPTIONS
• Steady state
SKETCH
PROPERTIES AND CONSTANTS
the specific heat of dry air (cpa) = 1059 J/(kg K) at 400°C
the specific heat of water (cpw) = 4178 J/(kg K) at 50°C
Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars appear
A) brighter. B) redder. C) larger. D) bluer. E) to have a higher radial velocity.
An aircraft starts at rest and is accelerated at 10 m/s2 for 30 seconds, at which time the aircraft becomes airborne. What is the distance traveled during the 30 seconds? Assume the acceleration is constant
A 0.50-m long solenoid consists of 1000 turns of copper wire wound with a 4.0-cm radius. When the current in the solenoid is 18 A, the magnetic field at a point 1.0 cm from the central axis of the solenoid is
a. 0.090 mT. b. 0.36 mT. c. 23 mT. d. 36 mT. e. 45 mT.