Sound and the Doppler Effect

What is the Doppler effect?

• The observed change in frequency of sound or light because of the relative motion of a wave source and the observer.

• The observed change in amplitude of sound or light because of the relative motion of a wave source and the observer.

• The observed change in wave speed of sound or light because of the relative motion of a wave source and the observer.

• The observed change in equilibrium position of sound or light because of the relative motion of a wave source and the observer.

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NGSS.HS-PS4-1

You stand on the sidewalk next to the street. A fire truck is moving towards you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

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NGSS.HS-PS4-1

You stand on the sidewalk next to the street. A fire truck is moving away from you. The frequency of the siren on the fire truck is 600 Hz.

What should the firemen on the truck hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

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NGSS.HS-PS4-1

A car moves at 20 m/s towards a whistle. The whistle is stationary. The whistle makes a sound with a frequency of 500 Hz. The speed of sound in air is 330 m/s.

What is the frequency observed by the driver of the car?

• 530 Hz

• 470 Hz

• 520 Hz

• 480 Hz

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NGSS.HS-PS4-1

A car moves at 20 m/s away from a whistle. The whistle is stationary. The whistle makes a sound with a frequency of 500 Hz. The speed of sound in air is 330 m/s.

What is the frequency observed by the driver of the car?

• 530 Hz

• 470 Hz

• 520 Hz

• 480 Hz

Tags

NGSS.HS-PS4-1

A fire truck is moving towards you. The fire truck moves with a speed of 30 m/s. You are motionless. The siren on the fire truck makes a sound with a frequency of 700 Hz. The speed of sound in air is 350 m/s.

What frequency will you hear?

• 765 Hz

• 730 Hz

• 660 Hz

• 645 Hz

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NGSS.HS-PS4-1

Sound waves are what kind of wave?

• Longitudinal
• Transverse
• Surface
• Electromagnetic

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NGSS.MS-PS4-1

NGSS.MS-PS4-2

If you want to change the pitch of a sound, you have to change the ___

• frequency
• amplitude
• speed
• volume

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NGSS.HS-PS4-1

This is the unit used to measure the volume of a sound. 

• Decibel
• Medium
• Vibration
• Oscilloscope

This is what you get when sound waves are reflected, or bounce back, off of a hard surface.

• Amplitude
• Pitch
• Volume
• Echo

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NGSS.MS-PS4-2