Question for Thesis... Jack the Ripper?

Question

Some of Jack the Ripper's victim's heads were nearly severed by the force of his attack. Coroner's reports indicate that only one cut was made to do this. I need to know how much force would be required to sever a human head - preferably with the physics/equations included in the answer.

I know this is an unusual question, but I have to know this for my Thesis on good ol' Jack.

Answer 1

There are quite a lot of variables involved in the equation.

You can calculate the force required from the "Gold standard" of decapitation devices the guillotine. A 30 kg weight dropping 226 cm is enough to sever the neck. Throw the earth's gravity into the equation and you can calculate the force the machine generated.

To calculate Kilo's per square inch that the guillotine blade delivered I suggest that you measure the average width of a neck. The Guillotine blade was pretty blunt so I would say you could calculate the cutting surface at about a mm. Jack's knives were sharper than the guilotine blade so calculate using a twentieth or a fiftieth of a mm.

The second attached link shows some the physics of applying the strikes that Jack would have used. Your angles of motion calculation in pendulums and levers can tell you the best blows to deliver the necesary force.

Good luck and I would like to see your thesis when you are done.

Answer 2

a million) Your thesis isn't new, through any skill. 2) you're going about it backwards. you mustn't be starting up with an assumption and then seek for evidence for it--you need to have studied the region and with slightly of success the evidence may lead you to the authentic. the in hardship-free words "evidence" of there being reproduction cats are that there are important ameliorations in M.O. between different murders. that's the familiar argument, and that's no longer conclusive through any skill.

Answer 3

A real sharp knife or large scalpel and an average sized male would be enough to cut through the neck, mostly flesh, tendons and soft muscle. Even the spine can be easily severed.

Answer 4

http://en.wikipedia.org/wiki/Jack-the-Ripper
http://en.wikipedia.org/wiki/Mary_Ann_Nichols
http://en.wikipedia.org/wiki/Annie_Chapman
http://en.wikipedia.org/wiki/Elizabeth_Stride
http://en.wikipedia.org/wiki/Catherine_Eddowes
http://en.wikipedia.org/wiki/Mary_Jane_Kelly

A well-sharpened blade requires little force to cut flesh. Have you seen what the chefs at Benihana can do with their knives.

Butchers routinely make single cut incisions in pork and beef with little effort. Perhaps your parents could let you experiment on tomorrow night's dinner meat. Would seem to me to be for a good cause. Or, you might go visit the local butcher and observe them in action.
http://www.actapress.com/PaperInfo.aspx?PaperID=22980
http://cat.inist.fr/?aModele=afficheN&cpsidt=2635412

Answer 5

Galina.

You are wrong about the "One cut". In most cases there were 2 cuts and in Kelly's case there were several.

There is a discussion about his topic going on at http://www.jtrforums.com

Answer 6

He may have used a sword. Not much force required then