Beats: A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with a frequency of 39.6 kHz. A car is approaching him at a speed of 35.0 m/s. The wave is reflected by the car and interferes with the emitted sound producing beats. What is the frequency of the beats when the speed of sound in air is 343 m/s?
A. 5000 Hz
B. 4500 Hz
C. 8490 Hz
D. 9000 Hz
E. 4250 Hz
Answer: D
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Energy Conservation With Conservative Forces: Assuming negligible friction, what spring constant (force constant) would be needed by the spring in a "B-B gun" to fire a 10-g pellet to a height of 100 m if the spring is initially compressed by 0.10 m?
A. 20 N/cm B. 20 N/m C. 200 N/m D. 2000 N/cm E. 0.0020 N/m
Pressure in a Liquid: The Tonga Trench in the Pacific Ocean is 36,000 feet deep. Assuming that sea water has an average density of 1.04 g/cm3, calculate the absolute (total) pressure at the bottom of the trench in atmospheres. (1.00 in = 2.54 cm, 1.00 atm = 1.01 × 105 Pa)
A. 1.1 × 103 atm B. 1.1 × 108 atm C. 1.1 × 105 atm D. 1.1 × 106 atm E. 2.1 atm
The hydrogen spectrum has a red line at 656 nm, and a blue line at 434 nm. What is the first order angular separation between the two spectral lines obtained with a diffraction grating with 5000 rulings/cm?
A. 7.7° B. 16.6° C. 6.6° D. 3.2° E. 19.2°
According to the nebular theory, how did the Kuiper belt form?
A) It consists of objects that fragmented from the protosun during a catastrophic collision early in the formation of the solar system. B) It is material left over from the interstellar cloud that never contracted with the rest of the gases to form the solar nebula. C) It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet. D) It is made of planetesimals that formed beyond Neptune's orbit and never accreted to form a planet. E) It is made of planetesimals formed in the outer solar system that were flung into distant orbits by encounters with the jovian planets.