Comments on: Death by Bocce

By: rachelle

rachelle — Mon, 27 Sep 2004 23:29:07 +0000

that’s a lot of violations for the new owners!! ew ew ewwwwwwwwwwwwwww!!!

By: HESS

HESS — Mon, 27 Sep 2004 22:08:51 +0000

more info on Leo's: http://www.newcitychicago.com/
chicago/3363.html http://w20.cityofchicago.org/health/
search/inspectiondate.jsp?eid=1059270 (maybe too much info)

By: CJ

CJ — Fri, 24 Sep 2004 23:23:38 +0000

Bocceball + Rachelle’s head = (ouch*10)

By: ChrisM

ChrisM — Fri, 24 Sep 2004 19:54:33 +0000

Good work Joe. You are correct, 30 feet isnt enough for a bocce ball to reach T. V., I should have realized this when I posted the request for a physics based solution.

Also I agree downward force other than gravity is probably minimal under the circumstances as we know them.

Based on your formula a fatal injury to dear Rachelle seems unlikely; concussion perhaps. But still who needs a concussion? So glad the ball missed!

By: joe

joe — Fri, 24 Sep 2004 19:17:48 +0000

True, if it were thrown the force would be greater. However, I would assume the ball were thrown out the window, giving the ball a horizontal velocity component directly out the window, but no vertical velocity component in the downward direction. Assuming that no one actually leaned out the window and threw the ball straight down, I would figure that the ball was being thrown around the home and went through the open window. Also, the ball likely was not thrown out the window with much horizontal velocity or it would have likely cleared the sidewalk and landed in the street or struck a car.

I think the assumption I made most likely to be incorrect is the 30ft drop, but being that we are still at present unsure which window the ball came from, I thought I’d make a worst case estimate.

By: curious

curious — Fri, 24 Sep 2004 19:17:13 +0000

But has anyone figured the percentage of geeks that read rachelleb?

By: Richard

Richard — Fri, 24 Sep 2004 18:45:15 +0000

Cool, an engineer! Very concise analysis. You forgot to mention however, that you assumed the initial velocity of the ball to be zero, meaning the ball was just dropped. If it were actually thrown, the force would be greater.

By: Joe

Joe — Fri, 24 Sep 2004 05:51:16 +0000

Sounds like an interesting engineering problem to me. Let’s see what we come up with:

Clearly the ball hasn’t hit terminal velocity yet. Therefore, we can determine it’s velocity using:

V = (2*g*h)^.5

g = 9.8 m/s^2

if we assume h = 30 ft, 30 ft = 9.114 m (disregarding Rachelle’s height, which is considered unknown at this point)

Substituting, V = 13.387 m/s

To determine the energy with which the ball would strike, we use simple kinetic energy and observe that:

K.E. = 1/2 * m * V^2

An official bocce ball weighs 2 lbs. 2 oz., or equivalent to 0.964 kilograms. Since we’ve established V, we can solve for the kinetic energy:

K.E. = 86.4 Joules (approximately)

For comparison purposes, a 4 oz. baseball thrown at 100 mph by a professional pitcher will strike with the energy of approximately 113 Joules. People have been killed by getting hit in the head with a baseball, but it is very rare.

The basis of these calculations involve the assumption that the head remain stationary during striking and absorb 100% of the energy of the traveling object. If one knew the spring stiffness of the human skull, one could determine how much the skull would deflect. Then, if one knew how much strain the skull could withstand without cracking, one could calculate the strain from the deflection and determine if it would crack the skull.

In conclusion, it isn’t likely this fall bocce ball would have cause extreme damage upon striking Rachelle’s head, but I’d be almost certain she’d have either a concussion or a very, very bad headache.

By: Richard

Richard — Thu, 23 Sep 2004 19:43:16 +0000

I think the force would depend on weather it was just dropped or actually thrown out the window. Either way, I don’t think it would have killed you, but if it hit you in the head it probably would have knocked you out.

By: ChrisM

ChrisM — Thu, 23 Sep 2004 19:38:03 +0000

Some geek (not that I should talk as being a former programmer!) figure out the terminal velocity of that ball considering weight that Rachelle gave and surface area of the ball. How much force was there after the 25 foot fall? Enough to be fatal?(off the top of my head I’d think yes) We need to find this out I think better for Rachelle to know one way or the other how near she came to a “near death experience”

In any event so glad you werent hit Rachelle. I think you woulda been well with in your rights for a screaming fit at the man even in front of his kids but you probably were kind of dazed and perhaps not your style.

Ma Bowden it is cause to be thankful the ball missed Rachelle yes indeed. The hand of God or the hand of randomness caused the miss? Tough question for me to answer.