Falling in a micro-gravity scenario?

Question

Let’s say we have a micro-gravity environment where people are staying afloat in the air because they have wings or some other means of resisting the low gravity, but then for some reason they find themselves bereft of that ability and start being pulled by the gravity… would they break their legs or be killed outright when they fell to the body generating the gravity, even though the gravity is low? How would that be calculated?

I am thinking of a dwarf planet with the same mass and gravity as Ceres. This planetoid has an earth-like atmosphere (hand wave that part for now). Characters there can float/fly, but an accident creates the scenario where one is lost and is being pulled by the gravity. What happens when he/she finally “crash lands”?

Edit-

Here's the scenario in more detail: human astronauts find this microgravity environment. Small planetoid/dwarf planet, approximately the size of Ceres, that has an atmosphere that is just like Earth's (again never mind how). The creatures there can keep afloat in the sky with their wings.

One of the astronauts goes exploring using a "jet pack" to fly around. A creature attacks him, damages the jet pack, and the astronaut is left with no means of getting around. He's just floating there. No one comes to his rescue. Sooner or later the gravity, though low, does pull on him and he starts "falling".

Barring a rescue or any ability of his own to "float/fly" what happens next? When he hits the ground does he go splat or does the lower gravity give him any chance of survival?

Answer 1

This question is ultimately about terminal velocity.

The equation to compute this is...

$$\sqrt{\frac{2mg}{ρAC_d}}$$

where m is the mass, g is acceleration due to gravity, ρ is the density of the fluid through which the object is falling, A is the projected area of the falling object, and $C_d$ is Drag Coefficient.

Given your Assumptions

1. The size of Ceres
2. Earth-like Atmosphere (handwavehandwavehandwave)

We can determine that your environment has an acceleration due to gravity of $0.28m/s^2$. The earthlike atmosphere gives us a density of $1.23kg/m^3$.

Assuming our falling person has the good sense to go belly-down for descent, an 'average human' would have a mass of $90kg$, and a projected area of $0.7m^2$. A splayed human has a Drag Coefficient of about $1$

So...

$$\sqrt{\frac{2*90*0.28}{1.23*0.7*1}}$$

Solving gives us...

$$V_{terminal} = 7.65m/s$$

Or, about 17 miles per hour at the low-end.

To check on the high-end, if the falling human assumes the narrowest possible profile, their projected Area is reduced to $0.18m^2$ and their Drag Coefficient is reduced to $0.7$. Re-calculating based on this gives us...

$$V_{terminal}=18.03m/s$$

Or, about 40 miles per hour.

So, depending on how they orient their body while falling, our plummeting human can reach a peak speed of between 17 and 40mph.

For comparison's sake:

17mph is about the speed at which a parachuter generally hits the ground. You need to know what you're doing to not get hurt, but even a bad landing is survivable with relatively minor injuries.

40mph is about how fast you'd hit the ground on Earth if you jumped off a 6 storey building. You might live, but you're going to break bones.

Disclaimer: this is a worse-case scenario that assumes the falling individual falls from a great enough height to achieve Terminal Velocity, and does nothing to arrest or slow their fall...like flapping. In a microgravity environment with earth-like atmosphere, that will make a difference.

Main Source, Secondary Source

Note: This question includes an assumption from the comments that has not yet been included into the main question