4. would two observers standing on opposite sides of the truck hear the same pitch at the same time? explain.

Brief Explanations:

This relates to the Doppler effect. When the truck (source of sound) moves, the observer in front (where the truck is approaching) will experience a higher frequency (higher pitch) because the sound waves are compressed. The observer behind (where the truck is receding) will experience a lower frequency (lower pitch) as the sound waves are stretched. So, they won't hear the same pitch at the same time.

Answer:

No, the two observers would not hear the same pitch at the same time. This is due to the Doppler effect: the observer toward which the truck is moving will hear a higher - pitched sound (as the sound waves are compressed, increasing frequency), while the observer from which the truck is moving away will hear a lower - pitched sound (as the sound waves are stretched, decreasing frequency).