Riding down the road and a ambulance passes you should be quit. This usually means someone got hurt.
Soften... It is lower due to the Doppler effect. Decrease =]
When an object is moving in a particular direction, air resistance will be acting on the object in the opposite direction to the direction of travel.
Velocity (speed and direction) Wavelength (frequency)
they attract if they go opposite directions they repel
They should seem to have a lower frequency due to the Doppler effect. The same as when an ambulance passes, the siren seems to go down in pitch because the source is moving away from you, so the time it takes each pulse of the siren to reach you is perceived to be longer.
Frequency
The Doppler effect
frequency.
frequency.
That would be the Doppler shift of the sounds frequency as it approaches you and passes by.
No. Velocity is a vector, so it has both a magnitude and a direction. If the velocity of your car was heading in the positive direction, then the other car is moving in the negative direction. The velocities are NOT the same!
Frequency is the amount of times a wave passes through an area. Hertz is a measurement.