Unformatted text preview: /'\. 5. 6. 0r=v The siren of a police car at rest emits a predominant frequency of 1600 Hz and the
police car is overtaking you from the rear, at a speed of 200 km/h. You are
proceeding in the same direction at 50 km/h. a. What frequency do you hear initially?
b. What frequency will you hear, when the police car passes you and continues on at
150 km/h after you have slowed to 25 km/h to insure you don’t get in the way? During a training exercise a fast attack submarine making a speed of 10 knots
approaches a missile submarine which is stationary (0 knot speed). The fast attack
submarine then transmits a sonar pulse of 7.0 kHz. Upon hearing this pulse the
missile submarine opens a torpedo tube door and increases speed to 10 knots in the
direction of the fast attack submarine. Upon hearing the torpedo tube door g0 open
the fast attack submarine reverses course and increases speed to 20 knots. After this
maneuver the fast attack submarine transmits a second pulse at the same frequency.
At what frequencies does the missile submarine receive the first and second sonar
pulses? Assume the speed of sound in water is lSOOnl/s and that l knot is 2.0 km/h. 'Vm V’Va “"3 ~43. ...
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- Fall '08