Final answer:
In a situation where your radio is not working on the moon and you need to contact someone to rescue you, yelling or flashing a light would not be effective forms of communication. The best way to communicate in this scenario would be to use visual signals like hand gestures or a written message.
Step-by-step explanation:
If your radio is not working and you need to contact someone to rescue you while on the moon, yelling or flashing a light would not be effective forms of communication. Sound waves do not travel in space, so yelling would not be heard. Light signals can be blocked by obstacles and may not be visible from a distance. In this situation, the best way to communicate would be to use a visual signal, such as hand gestures or a written message, to convey the problem to your friend on the moon. They can then take necessary action to seek help or inform others.