Final answer:
The statements about the position vs time graph of an accelerating object, the observed frequency at the speed of sound, wave-particle duality on the macroscopic scale, and the amplitude of waves affecting each other are all false. The concepts of a pebble creating a pulse wave in water and wave superposition with different frequencies are true.
Step-by-step explanation:
Answers to Physics Questions
Position vs Time Graph: The statement that the position vs time graph of an object that is speeding up is a straight line is false. When an object is speeding up, its position vs time graph is a curve that gets steeper over time, indicating increasing velocity.
Doppler Effect and Sound Speed: The observed frequency does not become infinite when the source is moving at the speed of sound, so the statement is false. Instead, a sound barrier is formed, and a sonic boom can occur.
Wave-Particle Duality: The concept of wave-particle duality does not exist on the macroscopic scale; it is a property of quantum objects like electrons and photons, hence the statement is false.
Pulse Wave: A pebble dropped in water is indeed an example of a pulse wave, making the statement true. A pulse wave is a single disturbance that travels through a medium, which in this case is water.
Amplitude Interference: The amplitude of one wave is not only affected by the amplitude of another wave when they are precisely aligned. Waves can interact and affect each other's amplitude through processes like interference, making the statement false.
Wave Superposition with Different Frequencies: Waves can superimpose or interfere with each other even if their frequencies are different, so the statement is true.