system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] In GoTG vol. 2, Gamora falls out of a ship and lands just fine after falling a hundred or so feet. In Infinity War, she straight up dies. Why?
gpt
Because the fall in Infinity War was 101ft.

But in all seriousness, it was probably a few different things.  Maybe Thanos used the reality stone to make sure the fall was fatal. Gamora was pretty shocked that Thanos cared enough about her to make her a sacrifice, it's possible she wasn't prepared to do what she had to to survive the fall. 

And a third option is because of the Soul stone.  It might not matter if the fall is technically fatal, it's just the act of sacrifice itself that kills the victim. Throwing Gamora off the cliff could just be symbolic, and the Soul Stone itself does the actual 'killing' as part of the exchange.