A Policeman in a Stationary Car Measures the Speed of Approaching

question 60

Multiple Choice

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 41.2 kHz.A car is approaching him at a speed of 33.0 m/s.The wave is reflected by the car and interferes with the emitted sound producing beats.What is the frequency of the beats? The speed of sound in air is .

• A) 9.2 kHz
• B) 4.1 kHz
• C) 4.6 kHz
• D) 1.2 kHz
• E) 8.2 kHz

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Definitions:

Abnormal Behavior

Actions, thoughts, or feelings that are atypical within a cultural context, potentially impairing functioning or causing distress.

Interpretation

The act of explaining the meaning of something, often used in the context of analyzing texts or behaviors.

Challenges Assertions

Involves questioning or disputing claims or statements, often to clarify truth or foster critical thinking.

Neurotransmitters

Chemical substances that transmit signals across a synapse from one neuron to another in the brain.