An object was dropped from the top shelf of a train carriage moving in a straight line. Is it possible to consider the movement

An object was dropped from the top shelf of a train carriage moving in a straight line. Is it possible to consider the movement of an object to be rectilinear in the frame of reference associated with the carriage? in a frame of reference related to the earth?

In the frame of reference associated with the carriage, the motion is linear;
In a frame of reference linked to the ground, movement along a curve.

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