Final answer:
The statement about the position vs time graph of a speeding object is false; such a graph is curved. The observed frequency does not become infinite at the speed of sound, so that statement is false. The use of refraction in fiber optic cables is true, allowing efficient signal transmission.
Step-by-step explanation:
When determining whether statements about physics concepts are true or false, it’s important to refer to the fundamental principles that govern physical phenomena. Here are the clarifications for the statements provided:
- Position vs Time Graph: The statement is false. When an object is speeding up, its position vs time graph will not be a straight line; it will be a curve, where the slope of the curve increases with time. This is because the velocity of the object is increasing, which is represented by a steeper slope in the graph.
- Observed Frequency and Speed of Sound: The statement is false. The observed frequency does not become infinite when a source moves at the speed of sound. Instead, this situation can lead to a sonic boom, which is where the sound waves pile up and create a shock wave.
- Refraction in Fiber Optic Cables: The statement is true. Refraction is indeed useful in fiber optic cables as it enables the light to be guided along the cable's path with minimal loss of signal.