Rubber Definition and 242 Threads

<Mentor's note: moved from a general forum and therefore no template> This is the equation of potential energy in rubber bands, however, I don't know how to calculate the inertia of the arm of catapults or get the k constant. And what does n mean? Basically, i don't understand the whole...

Homework Statement I did an experiment on how stretching a rubber band, affects the range or distance of a projectile shot. Variable list: Independent Variable Amount of stretching Dependent Variable Range or distance I created my catapults on my own and used two different rubbers bands...

Homework Statement I don't have a specific question, but I try to calculate very easy on a simple Gokart in a project. I try to figure out if there is a way to approximately determine what the damping ability of rubber wheels is because I don't have any suspension on it. Homework Equations I...

Homework Statement A 10 kg rubber box is resting on a concrete floor. A force of 200 N is then applied to this box in a horizontal direction. What is the magnitude of the friction force on the box? Homework Equations This is a question about applying Newton's laws so Fsmax = μs η and η = mg...

Homework Statement A uniform thin circular rubber band of mass M and spring constant k has an original radius R. Now it is tossed into the air. Assume it remains circular when stabilized in air and rotates at angular speed ω about its center uniformly. Derive an expression for the new radius...

Stretching a rubber band increase its mass due to e=mcc, but how?

Hello! I'm having a bit of an issue here, and I came across this site while searching on how to dissolve plant matter. The thread I found had some ideas, but said a reason would be needed before any concrete advice could be given. So here's my request - I need to instantaneously dissolve plant...

When I was 6 or 7 I decided to make a bow and arrow one day. I had never seen or handled one in real life, but it was intuitively obvious to me from TV that they way to do this was to tie the ends of a stretched rubber band to the ends of a stick. This would have worked, after a fashion...

Can anyone here settle(or contribute to ) a question that is ongoing at another forum? Who came up with the idea of the rubber sheet analogy in Relativity? Some there have wondered if it was the "rubber sheet geometry" as topology was described as ,apparently that may have ,perhaps...

Imagine that we wanted to build a slingshot, using one piece of rubber attached to two hooks - each on a side. We use a rubber, whose spring constant is k. My questions are: 1. If we began to string that slingshot and the rubber would begin to fold, what would happen with the string...

Hi all We are having a debate regarding peroxide cured EPDM where we a few employees are saying peroxide cured EPDM is food safe and can used as an FDA compliant material; the other group are saying that peroxide curing does not make it food safe. I lean more towards it is because the peroxide...

A friend of mine posed a question; if you take a rubber ball and bombard it with electrons, what would happen? I posited that some of the electrons would likely stay on the surface of the ball, giving it a negative charge. I then suggested that if under the "right" conditions you may be able...

I haven't studied materials in depth, but I would assume that something like rubber would make a good insulator because of its bounciness. The molecules of a substance contained in a rubber container would collide with the walls of the container in a very elastic collision, and the kinetic...

Hey there, I'm struggling in finding the useful equations to determine some conformability parameters for a finite elastic material (EPDM) compressed on a rigid slightly wavy surface. I would like to optimize the thickness of the elastic material in terms of indentation depth and thus contact...

I want to know the what is the effect of temperature on modulus of rubber, mathematical expression will be helpful

Homework Statement We place a rubber on the edge of a rotating disk. What forces act on the rubber? At what angular velocity, why and in what direction will the rubber fly off the disk? Homework Equations http://images.tutorvista.com/cms/formulaimages/83/angular-speed-formula111.PNG The...

Hello PF! I have a project/competition in freshman college Aerospace that calls for a plane that can stay in the air for as long a time as possible while going as far as possible. The requirements don't explicitly say we need rubber bands as a propulsion but pretty much prohibit everything but...

Homework Statement I need to explain for a lab, why the efficiency of a rubber band slingshot constant for different stretch lengths. I don't need math, just a general explanation of why kinetic energy of projectile/elastic potential energy in rubber band is constant. Homework EquationsThe...

Homework Statement Homework Equations $$ Z(1) = \sum_{i=1}^{} e^{\frac{E_i}{K_bT}} $$ where ##E_i## is each of the possible energy states available to a single link (in this case the right and the left states). $$ P=\frac{\sum_{i=1}^{} e^{\frac{E_i}{K_bT}}}{Z} $$ The Attempt at a Solution...

I'm aware of the concept of rubber as an entropic spring and how increasing the temperature increases the modulus/stiffness of the rubber. I've seen the experiment of how heating a strip of rubber supporting a load will cause it to shorten. But also a rubber will transition from its glass-like...

I am trying to find out what material that cowhide or vulcanized rubber will bounce off the most? (High school student working on a patent, so really not too experienced with materials engineering.)

I am looking for a simple number which is the potential energy that can be stored in rubber. ( Joules per gram or something similar ) I know there are a number of forms of rubber and I keep reading numerous articles on how to calculate the energy content of a rubber band. Can anyone just tell...

Homework Statement Calculate the magnitude and direction of the velocity of the rubber duck the second it lands? Homework EquationsThe Attempt at a Solution I'm confused, surely if it has landed then it has no magnitude or direction? as the object is now stationary.

I'm not sure if I'm supposed to post this here, if I'm not, I'm sorry. That being said, what kinds of rubber can be heated up to 30 degrees c without degradation but can be melted. I would like to sandwich a heating filament between two sheets of rubber and seal them together with heat.

Homework Statement Picture- https://flic.kr/p/zi1ays The rubber stopper will be spun at a constant speed in a horizontal circle. The hanging mass is only in contact with the string.[/B] A) For the rubber stopper, state the forces and what they are exerted by and on B) Does the net force have...

Homework Statement A hot air balloon containing an AP Physics student ascends vertically at a constant speed of 8 m/s. While ascending, he accidentally drops his rubber duckie from the gondola of the ballong. Seven seconds after it is dropped the duckie bounces off a roof at point A and hits...

So I just learned Gausse's Law and it makes me think: People always say you're safe in a car if it get struck by lighting because of the rubber tires (odd, because tired are like 90%carbon) but isn't it also because a car is a Gaussian sphere? The interior is insulated, sort of, right? If this...

Hey guys ! :) Last week I went on a Trip to this place 3500 ft above sea level, as I was walking my rubber boots got stuck on a big pile of mud (almost 30 to 40 cm) of my boots. I managed to take one out but the other was so stuck I had to play the natives to help me get it out. So my question...

Homework Statement From the experiment I did my force was equal to 0.0686N +/- 0.00196N and my x (rubber band stretch) was equal to 0.003m +/-0.002. The question asks to determine the force constant k +/- ∆k. Homework Equations F = kx k = F/x ∆k = |k| ∆x/x +∆y/y The Attempt at a Solution k...

Dear readers, For a Biomedical Engineering project I have to develop a model for the respiratory system of a neonate. This will be done by using pressure/volume data of the lungs. To model these, I would like to use a rubber balloon. However the calculation are more difficult than I thought...

Hello, first of all, this isn't a homework/school related question. Long story short, my father works for a chemical plant and a few of their valve/piston/transfer system things have been breaking, which he assumes is because of too much force. With everyone in a dispute and doing their own...

Homework Statement Two identical brass plates, each 0.5 cm thick, are separated by a rubber spacer of thickness 0.1 cm which has the same cross sectional area. If the outer surfaces of the brass plates are kept at 0 °C and 100 °C respectively, calculate the temperature at each side of the...

I have a question on GR. To what extent is the rubber sheet analogy correct? To be more specific, in that analogy, an object with mass M bends the 2-D space (the sheet) into a third dimension (the sheet goes downward). Does this imply that in out universe, an object with mass bends the spacetime...

Homework Statement For a stretched rubber band, it is observed experimentally that the tension f is proportional to the temperature T if the length L is held constant. Show that: a) The internal energy U is a function of temperature only b) Adiabatic stretching of the band results in an...

Okay- first off, I know enough science to sound like an idiot, so please be gentle :-) Now, IF you had a dragon that generated an electrical charge, it wouldn't be able to direct it, lightning-style, without being able to generate an opposite charge at it's target- right? So in essence, to shot...

I need to find the impact force that can be absorbed by these spacers as shown in the image. The spacers are radially distributed over the shell, and they are supposed to dampen any external impact loads to reduce the effective stress inside the inner shell. Since the FEA model is not showing...

Hello, I am studying and trying to understand Powertrain / Engine mounts used in automotive such as these: http://images.gasgoo.com/MiMwMDRfMDA0Izc4MDA3NzIwMA--/auto-part-engine-torque-strut-mount-engine-mounting-for-buick-enclave-chevrolet-traverse-gmc-acadia-25840458.jpg...

Hi, I'm a second year Design Engineering student. This year we're having some basic physics class. We're doing projects on potential energy at this moment. I'm having a problem with the following; The assignment: The teacher assigned us that only 6 Joules of potential energy may be used to...

Here's what I'm trying to paint: http://www.forcefieldbodyarmour.com/product/net-upgrade-armour-flat/2418 I'm trying to paint this black. Can i paint these yellow pads with some sort of non toxic spray paint? Or what about plastidip (which i think is nontoxic). I was even thinking of using a...

Homework Statement If a 2.5 kg rubber ball is rolled across the dry concrete floor with an acceleration of 4.0 m/s^2[E]. Determine the friction force required to stop the ball. (Drawing a free body diagram will help illustrate this situation) Homework Equations Fk= µk(Fn) F=maThe Attempt at a...

Homework Statement Homework Equations p=mv[/B]The Attempt at a Solution My thoughts- Answer is C as KE is not conserved since velocity of ball has decreased. Option A also seems correct.[/B]

Does this mean if I had a rubber band and weighed it, then stretched and weighed it while being stretched out, that it would weigh more at that time? Since at that time it has stored energy, which equates to mass?

Homework Statement "You have a 1 km long rubber band with one end attached to the wall, and the other in your hand. The bug begins to crawl towards you on the rubber band, starting from the wall, at a rate of 1 cm/sec. As he crawls the first centimeter you extend the rubber band 1 km; when he...

Homework Statement Homework Statement [/b] The purpose of this lab is to determine the mass of a rubber stopper being swung in a horizontal circle. I made an apparatus that resembles the picture attached, with a string (with a rubber stopper on one end, and a weight on the other end) put...

Homework Statement A solid rubber wheel of radius R and mass M rotates with angular veloctiy \omega_0 about a frictionless pivot. A second rubber wheel of radius r and mass m, also mounted on a frictionless pivot, is brought into contact with it. What is the final angular velocity of the first...

A rubber sheet (thickness 0.2mm) was mounted in an open-type Ussing chamber (6mm aperture) such that hydrostatic pressure could be applied to one side and the resulting inflation of the membrane tracked with an OCT instrument (OCT: ocular coherence tomography). From the geometry of the membrane...

Hello i need to know what should i do, Consider i have a box, top half and bottom half. so now i have to hold the top half and bottom half together with the rubber band then how do i know what rubber band will be enough to exert force so that both parts of box are hold together. also i...

Hey Guys, Can anyone tell me why the damping properties of rubber will decrease as the strain amplitude increases? Thanks

Model aircraft display a wide range of aerofoil shapes, and many of these models fly despite the shape of the cross section of the wing. Models with flat wings, cambered wings, thick wings, thin wings - all of these fly succesfully. What is the function of aerofoil shape on free flight...

Homework Statement The equation of state for a rubber band with temperature T is \mathcal{F}=aT\left[\frac{L}{L_0}-\left(\frac{L_0}{L}\right)^2\right] Where \mathcal{F} is the tension, L is the stretched length and L_0 is the unstretched length a) Write the Central Equation for the...