A spacecraft descends vertically near the surface of Planet X. An upward thrust of 25.0kN from its engines slows it down at a rate of 1.20m/s^2, but if an upward thrust of only 10.0kN is applied, it speeds it up at a rate of .80m/s^2. Apply Newton's second law to each case, speeding up or slowing down, and use this to find the spacecraft 's weight near the surface of Planet X.
F = ma
The Attempt at a Solution
Okay, I'm confused about how if 25.0kN force is applied, then it slows down but 10.0kN part will speed it up. I guess maybe that's why my method is wrong and I keep getting the wrong answer. This is what I'm doing: since I have the force and acceleration, I converted kN to N and divided by its acceleration to find the mass. Then I take the mass x gravity = weight, converting it back kN. Pls help me, where did I go wrong?