This is a maths question I need to have completed today, but I don't know how to do it!

"What is the probability that you will get hit by a fragment of a hand grenade assuming you stand 3 meters from the explosion?"
"Assume that the grenade weights 600 grams"
"Assume that the explosive inside weights 60 grams"
"Assume that each fragment will weights 2 grams"

Using only this data, how can I solve this problem?

2. Originally Posted by RichardtheMath
This is a maths question I need to have completed today, but I don't know how to do it!

"What is the probability that you will get hit by a fragment of a hand grenade assuming you stand 3 meters from the explosion?"
"Assume that the grenade weights 600 grams"
"Assume that the explosive inside weights 60 grams"
"Assume that each fragment will weights 2 grams"

Using only this data, how can I solve this problem?
You can't.

The casing mass is $\displaystyle 600-60=540$gm, so if each fragment has mass $\displaystyle 2$gm there are $\displaystyle 270$ fragments.

Now we need some assumptions (which are in fact invalid). Assume the fragments fly out so that they have a uniform distribution over the unit sphere, and do not fall or decellerate etc. Then a body has an cross sectional area of about $\displaystyle 1$sq m, a $\displaystyle 3$m radius sphere has a surface area of $\displaystyle 4 \pi 9 \approx 113$sq m. So the mean number of fragments that will hit you is about $\displaystyle 270/113 \approx 2.4$.

Now assume that the number of fragments that hit you has a Poisson distribution with this mean.

RonL

3. Hmm, I'll need to check over my notes and review the question, (I wrote down the verbal question) maybe I missed something.
Anyways thanks for the help.