Question
The train is accelerating at a constant acceleration, and the car is moving at a constant speed.
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If the car were to come to a stop, which of the following observations would a passenger in the car make about the movement of the train compared to when the car was moving?
The train would appear to not be moving.
The train would appear to be moving at a constat speed.
The train would appear to be accelerating more quickly.
The train would appear to be accelerating more slowly.
image.png
If the car were to come to a stop, which of the following observations would a passenger in the car make about the movement of the train compared to when the car was moving?
The train would appear to not be moving.
The train would appear to be moving at a constat speed.
The train would appear to be accelerating more quickly.
The train would appear to be accelerating more slowly.
Answers
GPT-5 mini
None of the four. It would still appear to accelerate at the same rate.
Reason: adding or removing a constant velocity (going from the moving car to being at rest) does not change the train's acceleration — Galilean relativity. Only while the car is actually decelerating would the perceived acceleration change (during braking the train would momentarily appear to accelerate even more). Once the car is stopped, the observed acceleration of the train is the same as when the car was coasting.
Reason: adding or removing a constant velocity (going from the moving car to being at rest) does not change the train's acceleration — Galilean relativity. Only while the car is actually decelerating would the perceived acceleration change (during braking the train would momentarily appear to accelerate even more). Once the car is stopped, the observed acceleration of the train is the same as when the car was coasting.