Plastic Definition and 278 Threads

Hi! I have this experiment, that keeps getting me frustrated. The experiment is simple: We have hot water and a long plastic tube with one end closed. We simply measure how much water is in the tube and from that we get the water volume (water is in cylinder shape). But there is something I...

Homework Statement One charged plastic ball is vertically above another in a test tube as shown. The balls are in equilibrium a distance "d" apart. If the mass of the upper ball is reduced by a factor of four, the distance between the balls in the test tube would become : 1) 4d 2) 8d 3)...

1. In tearing a paper towel or plastic bag from a roll, why is a sharp jerk more effective than a slow pull 2. I found this answer online A quick, sharp jerk means a greater acceleration and a greater acceleration means a greater force. And it is force that tears the paper towel or...

http://postimage.org/image/urnvnzkhz/ I was watching a tv show (the astute watcher will recognize it as How I Met Your Mother), when I saw one of the characters holding this thing (the curved plastic measuring-thing). My dad used to have one of those on his work bench, and I used to play...

Hi, Does anyone know what the name of this joint is? And if possible where i could buy a plastic version in Australia or online? Thanks in advance!

I think this belongs in set theory? I may be wrong though. I always enjoy a good math problem, and my niece made me think of something that I couldn't figure out an easy way to get an answer. She likes making those plastic bracelets with that plastic chord with the different colors and...

I'm working on building an enclosure for a machine that is to go on display in a foyer. The machine is about 2x1x1.5m and its primary purpose when switched on is to show how dynamic components work together. My considerations include: Cost: Need something relatively cheap Strength:High...

My new plastic toy has a strong chemical smell, does anyone have any suggestions on how to remove this smell? Thanks in advance for any suggestions

is there a simple way to determine the section modulus of a member made of a W and WT shape welded together, one on top of another about the x-axis. the steel manual has the properties for the individual sections; would the section modulus of each be able to be added together or will i have to...

Hi, I have to calculate the amount of times a 76g polypropylene lunchbox must be used in order to justify its purchase over disposable 2g polyethylene snaplock bags, in terms of the life cycle energy of the two products. However each time the polypropylene box is used it must be washed using...

Hi there, My teacher gave me a homework, but this Theory of Plasticity is new and difficult to me. He has calculated the strain according to path (1), now I have to do with the path (2) and (3). This is what he did with path (1): ε11=∫(1/E)dσ11 +...

Hi, sorry if this is in the wrong forum. I have a physics problem I do not understand: Jim is removing a piece of plastic wrap from a large roll. However, he is finding that this is difficult because the piece of plastic wrap keeps trying to stick to the roll. If the charge on the piece...

I need to Calculate the Skin Effect of water in a tube of X Diameter or Surface Area... The length of the Flow in the pipe would be 200 mm. I know that is short but it matters in this instance. The pressure of the water would be around 15 bar. I will post the flow rate through the pipe as soon...

Anyone have an update on this development? Is it a viable solution? Are the mushrooms tasty? :) http://aem.asm.org/content/77/17/6076

Is there a type of plastic that has a low melting point or better a low soft temperature? What we need is to blow up a ball (3-7 cm in diameter), cover the ball except a 6mm hole, let it dry, and then removes the plastic ball through the 6mm hole. So to remove the plastic it needs to be soft...

If gravity distorts space-time, does space-time return to equilibrium when the gravity mass is gone (let's say it vanished instantly)? If so, what happens to other satellite masses that are caught in the same gravity well? Does space-time just instantly slip out from under them? Or do the...

A plastic ball is inflated enough to produce tangential stresses. Stress X = Stress Y = 2000Kpa The radial thickness of the material is 1.2mm brfore inflation. Find the thickness after inflation if the tensile modulus of elasticity is 3.4Gpa and the shear modulus is 1.4Gpa.

Homework Statement http://img683.imageshack.us/img683/7060/selection001l.png Homework Equations \epsilon^{pl} = \epsilon - \epsilon^{el} \epsilon^{pl} = \epsilon - \frac{\bar{\sigma}}{E} r = \frac{\epsilon_w}{\epsilon_t}The Attempt at a Solution I'm stuck trying to calculate \bar{\sigma}...

I created a plastic bottle and aluminum can crusher. I researched and found out that my crusher should apply at least 175 lbf - 200lbf in order to crush the beverage container. My design idea is very similar to that of a cold rolling manufacturing process. Although I have research the cold...

The question to the lab is How can the spring constant and muzzle velocity for a toy ball launcher be determined through physical measurements and energy conservation considerations? My lab group and I took our pastic ball launchers(pretty much toy guns) and shot them straight up and measured...

I have a cylinder of plastic (polypropylene). It is 1 meter in diameter and 1.25 meters long. It starts out at an even temperature of 100 C throughout. I put it into a 135 deg heated room with lots of air moving around it, and I hold it in the air so that every surface is exposed to the hot...

Hello, I am looking for something to keep plastic parts warm and pliable. We have plastic discs that need metal pins snapped into some grooves and they snap wayyy to tight. We checked with a vendor and the material is still within spec, but I cannot change the material It takes one minute...

The link is to an article that describes the history of plastic combustion engines! The reason they are not in your automobile is that those who are experts don't like the idea. There are incentives in the U.S. to make cars more fuel efficient by some 5 years from now but the plastic combustal...

I'm having a significantly harder time finding information on this than I thought I would. I'm trying to write a small report on the chemical processes that recycled plastics are put through, but I can't seem to find much information on the methods used to disinfect various plastic polymers...

Hello, I have somewhat of a difficult question. First of all I have to say I am not an engineer. I need help in identifying this type of plastic. I am well aware that visual identification alone is almost impossible but any help would do. If possible, could one provide a supplier of this kind...

Hi All I am doing an experiment where I am analyzing how the volume of water in a plastic bottle affects the time taken for it to roll down an elevated ramp and particular distance along a horizontal plane. I need rigorous theory for this experiment which includes moment of inertia, fluid...

I have a plastic disk 0.5" in diameter whose radius of refraction is supposedly non-uniform. It will vary by 0.015 at most from the center to the outside. I need to come up with some method of measuring the refractive index locally. I have access to: helium neon laser a photodetector and...

So my mother buried her cat 5 years ago this month. I remember I wasn't home back then and it was a hard time. Yesterday we were talking about this and she asked me if I think the body is completely gone, and I said of course until she mentioned she put the cat in a plastic bag before buring it...

Results show me that if I increase the volume of water inside a bottle the time taken for it to roll down a ramp and then a particular distance along a horizontal plane increases. How would we explain this relationship.

I took a cube polycarbonate sample and put a laser through it (perpendicular to a face). When light crosses both faces (front and back), some of the light will reflect while some goes through. My questions are: 1) For the light that reflects off the first face and goes straight back into the...

The title says it all what are the differences between Pseudo-plastic and Bingham plastic?

I have a project where I need a flat sheet of plastic that's about 1 foot by 1.5 feet and about a quarter inch thick, but probably less than that. It doesn't have to be exactly that size. It can't be brittle either, it needs to be able to bend some. I don't know where to get something like...

A few weeks ago a 23 year old british reality tv star died getting breast implants the size of basketballs, she was barely 5 feet tall. Heidi Montag is in the news about all of her plastic surgery. She was pretty before she changed her face, now, not so pretty, IMO. Here are before and...

So I'm on my last try for this question, and I could really use some help, I'm completely clueless.. Two waves of light in air, of wavelength λ = 460.0 nm, are initially in phase. They then travel through plastic layers as shown in Figure 35-36, with L1 = 4.00 µm, L2 = 3.50 µm, n1 = 1.20, and...

Ok, I have an invention, it's a clip.. and I'd like it to be made out of plastic. What I need out of the plastic is "spring back" quality. I need it to where one can pry it open, and it'll return back to it's original shape. This is a small device, and the plastic only needs to be about...

Hey PF, I normally frequent the EE portion of this board, but I had a question about plastics and plastic injection molding. A buddy and I have an idea to create a rather small and specific plastic object in large quantities. We thought that to create small prototype quantities, we could...

I am looking for this part.. I was thinking that i could find it on http://www.smallparts.com" but i have no idea how it might be called, it's a 10mm plastic holder of plastic tubes, here are some images I've designed: http://img153.imageshack.us/i/holder1e.jpg/"...

Hi Guys, I am new here, but I have a quick question. I had a somewhat tepid liquid in a plastic soda plastic 2L bottle When I tightened the cap to close it all was well and normal After a day a portion of the top of the bottle deflated, as if oxygen was sucked out Can someone...

Homework Statement An open plastic soda bottle with an opening diameter of 2.7 cm is placed on a table. A uniform 1.95-{\rm T} magnetic field directed upward and oriented 21^\circ from vertical encompasses the bottle. What is the total magnetic flux through the plastic of the soda bottle...

Hello, I wanted to know which properties a foam plastic have in general and how it works in a Mattress. I have a Foam mattress is there any difference between hot and cold foam? My Mattress is a Foam mattress not a Spring mattress and it feels too hot after a while you lie on it...

Hi, I'm trying to understand the viability of making or having made - a hot -mould that can resize the neck of a standard cooldrink bottle. I want to reduce the neck of a 500ml bottle so that it fits loosely into another bottle's neck. So(ie) - to heat and compress the neck( threaded apperture)...

Hi all. I am now working on the uniaxial cold drawing on the plastic sheet (polybutylene succinate, a semicrystalline polymer). After uniaxial cold drawing, as expected, strength increased along the drawing direction/ machine direction (MD). Strength and elongation at break drastically...

Hi, does anyone know where to buy cheap plastic lenses online? I need lenses of 0.8-1.2mm diameter and 5-50mm F.L. Thanks

in the following question i am asked to find all the possible mechanisms, in the given state, and then when the "X" bar has an area of A and not 2A the answers are: when area of X=2A i) plastic hinge at D ii) yielding of Y and X bars iii) plastic hinge at C, yielding of "Y" bar...

http://www.stumbleupon.com/su/2RcIPs/blogs.discovermagazine.com/discoblog/2008/05/27/its-in-the-bag-teenager-wins-science-fair-solves-massive-environmental-problem/ Ok, interesting, but is this practical? Leaving aside the means by which you'd heat the mix to a cosy 37 degrees, what would be...

I discussed with my students that if force remains constant and mass decreases then acceleration increases (a=F/m). I also explained that if force remains constant and mass increases, acceleration decreases. I know that there are a number of variables that play into this next situation and I...

Homework Statement the graph below shows the behaviour of a sample of a metal when it is stretched until it starts to undergo plastic deformation. what is the total work done in stretching the sample from zero extension to 12.0mm? simplify calculation by treating the region xy as a...

My question is that would it be more environmentally friendly to burn plastics bags rather than letting them degrade? They take thousands of years to do so and even then many plastics do not completely break down beyond the molecular level...so instead of letting them hang around in the...

Homework Statement A sheet of plastic, n= 1.5, 25 mm thick is used in a bank teller's window. A ray of light strikes the sheet at an angle of 45 degrees. The ray leaves the sheet at 45 degrees, but at a different location. Use a ray diagram to find the distance between the ray that leaves and...

Homework Statement I have this lab and my goal is to find how far I should place a box if I was to catch a plastic leprechaun that weighs 22.4 grams fired out of an air cannon. I did this lab and the final velocity I ended with was 12.76 meters/sec (29.72 meters was the average distance and...