(a) At an air show a jet flies directly toward the stands at a speed of 1200 km/h, emitting a frequency of 3500 Hz, on a day when the speed of sound is 342 m/s. What frequency is received by the observers? (b) What frequency do they receive as the plane flies directly away from them?

What frequency is received by a stationary mouse just before being dispatched by a hawk flying at it at 21.6 m/s and emitting a screech of frequency 3400 Hz? Assume room temperature air.

An air controller on an aircraft carrier sees a jet fly over 81 meters above her and she hears the sonic boom when the jet is140 meters past her. What is the speed of the jet if the speed of sound is 344 m/s? (81/140)*344 m/s none of these. (140/81)*344 m/s O (140/344)*81 m/s

(a) What frequency is received by a person watching an oncoming ambulance moving at 120 km/h and emitting a steady 853 Hz sound from its siren? The speed of sound on this day is 345 m/s. Hz (b) What frequency does she receive after the ambulance has passed? Hz

A stationary speed detector emits microwave with frequency 3.0 x 10^10 Hz to detect the speeds of cars on a freeway. If a reflected wave, when combined with the outgoing wave, produces beats at a rate of 5000 S-1. If the speed limit in the highway is 110 km/hr, is the car exceeding speed limit?

Problem #6 You want to buy a lamp, and the store has only lamps of a nominal power of 150 watts. When you were ready to pick up a lamp, you observed that there were two piles one pile were incandescent lamps and the other LED lamps. You remember that in class we discussed about efficacy. Immediately, you find in your phone the following table Flux [lumen] 250 450 800 1100 1600 Power Power Power Power Power [Watt] [Watt] [Watt] [Watt] [Watt] Then you can answer the following questions: Incandescent 25 40 60 75 100 Halogen 18 29 43 53 72 1) incandescent lamp? CFL 6. 10 13 18 23 What is the illuminance flux of the LED 4 5 10 15 20 2) What is the illuminance flux of the LED Efficacy [lumen/watt] Incandescent Halogen Efficacy lamp? Average 3) Explain which one you will buy and the 10.0 11.3 13.3 14.7 16.0 13.1 13.9 15.5 18.6 20.8 22.2 18.2 reasons for your selection CFL 41.7 45.0 61.5 61.1 69.6 55.8 LED 62.5 90.0 80.0 73.3 80.0 77.2

(a) What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 833 Hz sound from its siren? The speed of sound on this day is 345 m/s.(b) What frequency does she receive after the ambulance has passed?

A bat flying at a speed of 5.7 m/s pursues an insect flying in the same direction. The bat emits a 49000-Hz sonar pulse and hears the pulse reflected back from the insect at a frequency of (49000 + 590) Hz. Take the speed of sound to be 343 m/s. What is the speed of the insect, in meters per second, relative to the air?

(a) What frequency is received by a person watching an oncoming ambulance moving at 105 km/h and emitting a steady 713 Hz sound from its siren? The speed of sound on this day is 345 m/s. (b) What frequency does she receive after the ambulance has passed?

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