# Power of flight vs weight of object in free fall

In my story there are people with super powers, but they only get to have one. So, if someone’s power is to start a fire, then they can’t also control it once it starts. My problem currently is with the power of flight.

My superhero can fly. She does not have any additional powers, such as super speed or strength. Being up in the air is exactly like standing on the ground. She can deadlift or carry the average amount/weight for a person of her size and fitness level, whether on the ground or in the air.

So, she and another person fall out of a plane and free fall until they reach terminal velocity. She manages to grab the other person, but now she has to arrest their free fall. Basically what happens at least once in every Superman story ever, but Superman has a ton of other powers while my hero does not.

Is this a deadlift situation, so if she could lift this person while both were standing on the ground, then she can stop their free fall using the same amount of strength? Or is she fighting against a force that is impossible for her to counter?

• Welcome to the site Alexandra, when you have a few minutes, please take the tour and read up in our help center about how we work: How to Ask. At the moment your question would seem to be about a story within a world, not about worldbuilding. As such I'm voting to close 'till you've read the terms, so you don't get low quality answers. Then you can edit the question to fit our requirements, which would put it in the review queue to getting reopened. Commented Jun 25, 2019 at 19:26
• It is up to you to define how the power works. Typically with superpowers people just choose whatever is dramatically appropriate and make up the rules afterwards to fit. Basically you can have it work anyway you want. Maybe the fall instantly stops. Maybe she applies force and the fall decelerates. Maybe the power is incapable of doing anything unless she lets the other person to fall. Maybe it stops her just fine but the other person isn't slowed is janked off her hands since human arms cannot stop a body falling that fast. Anything you want. Commented Jun 25, 2019 at 19:36
• @VilleNiemi It is up to you to define how the power works. No, part of the purpose of this site is to help people define how super powers work. Alexandra has given us the desired outcome, now we need to help her develop the rules of the super power. This should be exactly the kind of question we want to answer.
– JBH
Commented Jun 25, 2019 at 22:58
• Close voters: remember that people can give us the rules and ask for help with the outcome, or give us the outcome and ask for help defining the rules. What they can't do is ask us to do both at the same time. I like this question.
– JBH
Commented Jun 25, 2019 at 23:04
• Query is certainly not story based; nor is it not about worldbuilding. In this case, single factor super powers are part of the world's fabric. Strictly speaking, Ville Niemi is correct in saying that "it's up to you how it works". But if we follow such faulty logic, we might as well shut down WB.SE entirely, because that is the correct answer to every single query ever asked in this forum. JBH is correct: put your creative caps on and answer the dam question already! Commented Jun 26, 2019 at 0:22

If she can fly carrying a load, it means she can exert a force equal to her weight plus that of the load, against gravity.

The scenario you describe until terminal velocity can be described as an accelerated motion, starting from velocity 0 and ending with terminal velocity v. While this happens they cover a distance h.

Since she wants to stop the fall, it means she has to reach again velocity 0. With her power this can happen only if she is at an height at least equal to h above the ground. If so she will stop before impact. If not, she well hit the ground.

• her real problem is she cant get even close to plane altitude (partial pressure) and someone falling far enough to reach her will just tear her arms off if she tries to decelerate them. she needs to match their falling speed first then try to slow them down. This gives her a lot less room ot play with.
– John
Commented Jun 26, 2019 at 2:57

She doesn't fly. She simply uses her feet.

Flight is complicated. Let's break this down to something more simple. Your superheroine's power is actually that she can use her feet on any substance. For her, the only difference between walking up a flight of stairs and walking to a point above the local park is that in the first instance she's pushing against the stair treads and in the second instance she's pushing against air.

Or water... or fluorine gas... or anything else.

This solves the problem of how she can stop someone from falling. From her perspective, she's standing "on the ground." If she could catch a child from the first floor she can do the same thing at 35,000 feet. If she can carry a sack of potatoes, she can do so standing on the Atlantic ocean surface.

But there is a consequence. She can't fly. That's not the actual power. So getting to 35,000 feet takes time. However quickly she can run 6.63 miles, that's how quickly she can get to 35,000 feet. And if she can't carry that sack of potatoes for 6.63 miles without setting it down... um... she'll have a problem.

Developing super powers is fun because you need to come up with both the benefits and the limitations.

She can do it but it is going to be a lot of work.

1. Imagine I have the power to push a car. Dutch puts it in neutral, and steers (sort of), and I push because we have run out of gas. It is work for me but doable. He honks the horn to celebrate my efforts.

2. We are at the top of a hill but in addition to gas we have run out of brakes. It is a small hill but once back on the level, the car is rolling along at a good clip. I hustle around to the front and push backwards to make it stop. Little by little I can slow down the car as I am pushed along in front. Hopefully nothing is behind me. Dutch honks the horn some more.

Your protagonist is in the second situation. She and her load have considerable kinetic energy moving downwards. She must overcome that downward momentum to come to a stop just as I must overcome the momentum of the rolling car to bring it to a stop. She can only exert the force that she can exert and so she will need to exert it over time, slowing little by little just like me with my smoking sneakers pushing back on the rolling car. If she has enough time before she hits and she does not tire out, she can do it.

• If she can lift herself and whatever load she is able to lift this means that the net force pulling them down is zero. Air resistance will slow down their descent very quickly (but not instantaneously) from about 200 km/h (120 miles per hour) down to zero. Commented Jun 25, 2019 at 20:06
• That is right, @AlexP. She can use the air as a brake, if there is enough distance to do it. I like the idea that she thinks this is going to happen but realizes that she has miscalculated because they started too close to the ground and she is not used to free fall. She has to accelerate them upward or they are going to hit hard. It is a lot of work. Commented Jun 25, 2019 at 22:24