The discussion centers on the calculation of rain's velocity relative to a moving car, emphasizing the importance of vector addition over simple arithmetic. The velocity of rain with respect to the car is derived from the rain's velocity relative to the ground minus the car's velocity relative to the ground. Participants clarify that the "wrt" (with respect to) notation does not imply focusing solely on horizontal components. There is a consensus that vector addition is necessary to accurately determine the rain's velocity in relation to the car. The conversation highlights the need for further clarification from the original poster to resolve any confusion.
