What would the answer be here? i'm lost.

Question

A space probe is being prepared for a deep-space mission. The engineers have divided the trip into five segments based on the required changes in motion, as noted in the table. During which parts of the trip must the engineers apply the principles of general relativity? (Note that the velocities are listed as a percentage of the speed of light, c. The direction is positive when moving away from Earth and negative when moving toward Earth.)

Planned Space Probe Mission
Trip segment Initial velocity (% c) Final velocity (% c)
A                           0                         +90
B                         +90                       +90
C                         +90                        -90
D                         -90                         -90
E                         -90                            0

A. Segments A and B

B. Segments B and D

C. Segments A, B, and C

D. Segments A, C, and E

Answer 1

General relativity involves accelerations (change in velocity), which occur in segments A, C, and E.  The spacecraft is flying at a constant velocity (no acceleration) during segments B and D - special relativity would apply in these segments.