Knife Definition and 25 Threads

I have a question regarding the collision of two objects, specifically something heavy falling on something with a point. For example, if a 50lb ball of clay fell from 10 meters onto the point of a knife, would the knife's point have to withstand the entire force of the clay before the blade...

##v^2=u^2+2as## ##v=10m/s## Again ##v^2=u^2+2as## ##a=25 m/s^2## So ##F=(200*25)/1000## ##F=5 N## Wrong answer!

They say that a rotating knife thrown is more dangerous than a knife thrown straight I find it weird If the knife is rotating, it will experience more air drag than if thrown straight which will also depend on plane of rotation(For some reason, I don't know, it experiences more drag if...

Is any tool available for a person to use instead of putting their weak finger nail into the groove of one of the functions of a swiss army knife or victorinox knife in order to open that function? Some of our nails are just not tough enough to put into those grooves to pull the function out...

Hey guys, brand new here but looks like I'm in the right place :D I've got an OTF knife (a.k.a. "out the front," where the blade ejects straight out from the handle) that is held in the closed position with 1 lb, 12 ounces of magnetic force. I.e, upon measuring it takes 1 lb, 12 oz. of finger...

I have never posted a Q here before, but as an old knife and swordmaker, when I saw this article: https://phys.org/news/2019-06-french-scientists-metallic-hydrogen.html It suddenly piqued my interest: IFF one can create a large enough, meta-stable crystal of metallic Hydrogen, and were able to...

An open knife edge of mass 200 g is dropped from height 5 m on a cardboard. If the knife edge penetrates distance 2 m into the cardboard, the average resistance offered by the cardboard to the knife edge is:

Homework Statement A tradesman sharpens a knife by pushing it against a grindstone with a given applied force. The grindstone is 28kg, 15 cm in radius, is originally going at 200 rpm but is slowed down to 180 rpm over 10 s by applying the knife. The coefficient of kinetic friction is 0.20...

hi you'al, i hang in a knife forum and there is a lot of discussion on what steel is "best" for knife blades..latest fad/dream steel is some power made to steel from Hitachi some of what i wander is the "powder" made no for these steels and what adds to the properties of the steel the...

I was thinking about the principle of energy density and how sharp knives cut so easily because their surface areas are tiny and thus any force applied to them is imparted on this tiny area. So my question arises, does anyone know just how sharp the sharpest knife/ sword is? Let's no discuss...

It is not a folding knife. And it's too small to act similar to a "Granton Edge" that prevents slices from sticking. https://scontent-b-ord.xx.fbcdn.net/hphotos-xap1/v/t1.0-9/10868213_10152451162981394_4080056179223702862_n.jpg?oh=e21db53eb831b7a175d9c3a5b070f1d5&oe=54FD9088

When a throwing knife is thrown why does it only hit its blade end ( not the grip end)? The knife has been imparted with a spin and there is a 50:50 probability that its blade end will hit (actually a bit less). It would be better if you explain assuming the blade's CM has velocity 'v' and is...

I was having a discussion with someone far more expert than I and for whom I have a lot of respect. He was telling me that the path loss of a radio signal from A to B is not necessarily the same as it is from B to A. One of the reasons he mentioned is diffraction over a knife edge which in...

If I flick open a folding knife with a flick of my wrist, what force is that? Is it centrifugal force, centripetal force, or some other force?

Please refer to attached figure and help to give a formula of how to calculate the force "F". This is a task from real-world, which means that there was a damage with this machine and now it is necessary to know the mentioned force. The information that is available to complete the calculation...

Hello folks, my study of physics is 20 years old or so please bear with me. I enjoy sharp knives and blades in general and am curious about what is actually happening when I sharpen them. I know these steels are a matrix composed of different elements tightly bound by nuclear forces, but I'm...

hi , i am newbie here and reading through i find it ... stimulating.. now as to what brought me here.. i have wanted to look into art form of acid etching different knids of tempered steel used in stainless knife blades.. does anyone there know what mask coating will take a fine line...

I'm having a hard time finding some documentation on the thickness of a knife edge. I need to calculate the force to slice an apple. I found the skin bursting strength to be 1.1 MPa. That means that assuming the thickness blade to be 10.0 micro-meters and the max length of contact with the...

"Dead" man wakes up under autopsy knife http://africa.reuters.com/odd/news/usnN1499758.html

http://news.yahoo.com/news?tmpl=story&u=/ap/20050924/ap_on_fe_st/puppy_swallows_knife Six month old puppy swallowed 13-inch serrated knife. Lives with a 8 inch scar.

Hello, I just registered to these forums but already visited this place for a while. I have a question that fits this particular subforum (I hope). It is related to another hobby of mine, which is knife collecting/making. Let me give you first some background info on the subject, in order to...

i need urgent help can anyone suggest some link that clearly states the physical property needed for a stainless steel knife? i desperately need it today. thz any help will be GREATLY appreciated

Specially in the movies... i see people throw knives at enemy's neck or the head instantly killing them... some of the knife i saw.. fly straight without any rotations... how can you throw a knife that doesn't even rotate or spin... and travel straight with high velocity ? ( and the mass is...

Hi everyone! I need help on how to build a butter knife that gets warm. I know I need to put a nichrome wire in the blade but would anything go at the end? Would I connect the wire to a battery? How do I find out what size battery to use and make it so the blade gets to a specific heat...

If I cut a ball of mercury with a knife it forms into other balls why is this