# B Question about gravity, water and snow

1. Jul 28, 2017

### Rafael toledo

Suppose I fell from a mountain, which would hurt less:

A) Falling on a very huge pile of powder snow or
B) Falling on water

It's a serious questions! Thanks!

2. Jul 28, 2017

### Staff: Mentor

Hi Rafael. I'm guessing that A would hurt less because snow (at least certain types of snow) typically has air trapped in it and is able to be compressed. It also doesn't present a sudden, drastic change in density like moving from air to water does. But that's mostly a guess on my part.

3. Jul 30, 2017

### Buzz Bloom

Hi Rafael:

I believe the answer depends on some unstated assumptions. The following are some examples.

What do you mean by "fall off a mountain"? Is your fall off a cliff through the air, or are you sliding down a steep slope of the mountain? How high is the mountain, or more relevant, how far vertically do you fall? Can you control your orientation so that you fall with your body horizontal until you are near the water/snow (to minimize your velocity when you hit the water/snow), and then reorient your body so you enter the water/snow feet first with slightly bent knees (to minimize injuries)? What are you wearing? Assuming the fall itself does not cause serious injuries, you will likely end up deep in the water/snow, so what will you do to avoid drowning/suffocating in the water/snow? Perhaps you have a breathing device and an air supply with you. In that case, if you are in water, then perhaps you can swim to the surface and survive. If you are in snow, how will you get to the surface before your air supply is exhausted or you freeze to death?

Regards,
Buzz

4. Jul 31, 2017

### jbriggs444

The recorded cases of people surviving falls from very great heights (a mile or more) generally involve snow, trees, glass ceilings or something similar to cushion the impact. None of those cases involve landing in water.

The problem with landing in water is two-fold. First, water is largely incompressible. A high speed impact will involve very large accelerations. Second, after the impact renders you unconscious, water can drown you.

The recorded cases of survival have typically involved a witnessed fall with prompt aid rendered.