What season is it in your town when it is fall in the Southern Hemisphere

whichever one it is, it's definitely not one that you included on the list you provided.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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your answer is, orbit around the nucleus

i believe the answer is a hope it and is correct