Answer
If the trajectory is parabolic in one reference frame, it is sometimes parabolic in another reference frame that moves at constant velocity with respect to the first reference frame. In another reference frame, the trajectory could be parabolic, but it could also be linear.
Work Step by Step
If the trajectory is parabolic in one reference frame, it is sometimes parabolic in another reference frame that moves at constant velocity with respect to the first reference frame. In another reference frame, the trajectory could be parabolic, but it could also be linear.
For example, let's suppose a person on a train (moving at constant velocity) throws a ball straight up in the air. For a person standing on the train platform, the ball's trajectory is parabolic. However, in the train's reference frame, the ball's trajectory is a straight line that goes straight up and straight down. From the point of view of a person riding on a second train moving at a different constant velocity, the trajectory would appear parabolic. Therefore, the trajectory could be parabolic or linear, depending on the reference frame.
