Math/Physics question

You, your buddyare standing on a small small river (100 yards wide) with a steep hill that prevents you from running for the hills. Your enemy is on the opposite side of the river and he has a grenade in hand. While you are far enough way that he can't be certain of hitting you squarely, you are afraid of the shrapnel.

If you dive in the water, the water will protect you from shrapnel (unless it is inches from your face). But grenades work underwater as well in air.

Your plan is to dive in the water with just your head protruding. When he throws the grenade you will take a deep breath and swim to the bottom until after the explosion.

Your buddy is going to stay on dry land and simply run away from the grenade hoping to get far enough away to be out of shrapnel range.

While no action will absolutely assure you of safety, who is making the wisest move? Is there a better alternative.

This question is real, and there is a variation of it in the safety manual.

Close only counts in horseshoes and grenades ... but grenades with an air burst have a certain shrapnel pattern and even if you ain't shredded you can be a bit disoriented by the experience. Atleast if you see it coming in you get some warning.

Grenades in water that are close can leave you unwounded but minus two ear drums and that can really reduce effectiveness.

Shoot first.

When you let the enemy define the terms of the battle, you've already lost.

Does fishing with dynamite give a clue to the answer?

I voted to stay on dry land and run from the grenades. In the water the enemy will have a closer shot, swimming speed is slower, and I tend to think water would be a good conductor of the shock of the grenade.

If I were the enemy, and you went into the water, I would count how long you could stay under, and then time my throws just as you were coming up for air.

There is patently not enough information in this formulation to give a thoughtful answer.

Hydrostatic shock would seem to tell me to avoid the water.

Isn't the grenade in the water a bit luck a depth charge...

Why can't we all just get along?

Think like MacGyver......WWMD?

Just a question, how many people can throw anything 100+ yards? It would have to be in the air so long, that you could easily run away from it......I think.

Quote: steeldco

Just a question, how many people can throw anything 100+ yards? It would have to be in the air so long, that you could easily run away from it......I think.

Having thrown a grenade and having a good arm my max range was maybe 40 yards.

Quote: treetopbuddy

Having thrown a grenade and having a good arm my max range was maybe 40 yards.

Fully agree this is way beyond any realistic range. We had a guy who was a former college varsity javelin thrower and he could manage maybe 50 or 60 meters

Quote: Wizard

I voted to stay on dry land and run from the grenades. In the water the enemy will have a closer shot, swimming speed is slower, and I tend to think water would be a good conductor of the shock of the grenade.

If I were the enemy, and you went into the water, I would count how long you could stay under, and then time my throws just as you were coming up for air.

That would be the correct answer. If you managed to avoid shrapnel for an exploding hand grenade, you'd likely remain unharmed. If you stood at the same range to an underwater explosion, the pressure wave would probably kill you.

The atmosphere will compress and absorb some of the explosive energy greatly decreasing the lethal range of the explosion.

Water, however, is often described as incompressible. Your body's density is similar to that of the water. The wave would hit the air-filled pockets of your body and instantly compress the gases there, possibly resulting in blocked blood vessels, ruptured lungs, torn internal tissues and even brain hemorrhaging. Waves hitting the surface of the water or the bottom of the pool would bounce back, inflicting even more damage. You have no such boundary layers in water.

The official advice based on experiments done by British volunteers in WWII is to try and get your head out of the water as damage to your lungs and other internal organs may be survivable. If you are unable to get your head out of the water, it makes a big difference to get it near the surface. Technically the surface of water is called a "pressure release" because the direct and reflected pressure waves try to cancel each other out, rather than having a one two punch if you are deeper.

While clearly water's density will minimize the shrapnel damage, you are better off in air risking a limb than fighting massive internal bleeding.

I'm sorry pacomartin but the 100 yard separation issue has not been addressed properly in this thread. To say that the Wizard has given the correct answer is premature.......was Willie Mays the enemy?

100 yards... Unless the enemy is Peyton manning standing across the river, you don't have anything to worry about... Stay where you are and get low... Never run up a hill that doesn't have any cover (I.e trees, brush, etc.) it would be like duck hunt for the enemy watching you run..

I believe the kill range on q grenade is like 15 meter and the minor injury is 50 meters. (might be wrong, been a while since ive thrown one)