What is Rubber: Definition and 253 Discussions

Rubber, also called India rubber, latex, Amazonian rubber, caucho, or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds, plus water. Thailand and Indonesia are two of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers.
Currently, rubber is harvested mainly in the form of the latex from the rubber tree (Hevea brasiliensis) or others. The latex is a sticky, milky and white colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called "tapping". The latex then is refined into rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for sale.
Natural rubber is used extensively in many applications and products, either alone or in combination with other materials. In most of its useful forms, it has a large stretch ratio and high resilience, and also is water-proof.

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  1. 3

    Impulse of clay and rubber ball on the wall

    Homework Statement A 0.1 kg rubber ball and a 0.1 kg clay ball are both thrown at the wall with the same initial velocity. the rubber ball bounces, the clay ball sticks. Which exerts a larger impulse on the wall?
  2. S

    Cons. Momentum/Energy of rubber block blown up by explosive

    Homework Statement A small explosive charge is placed in a rubber block resting on a smooth (frictionless) surface. When the charge is detonated, the block breaks into three pieces. A 200-g piece travels at 1.4 m/s, and 300g piece travels at 0.90m/s. The third piece flies off at a speed of...
  3. W

    Most effective way to pinch a rubber tube?

    Hello, I am looking for the most effective shape to pinch a rubber tube. The most effective shape requires the least force. Given a tube of certain diameter/thickness, I want to know whether I should use a flat, curved, knife edged or whatever type of pinch and what thickness it should...
  4. S

    Equation for number of crosslinked polymer strand in rubber

    I am doing an experiment to estimate N, the number of crosslinked polymer strand in a piece of rectangular rubber. To do this, I attached weights to the rubber and measure the extension of the rubber when subject to the force. However, I found two equations that can be used to find N and they...
  5. R

    Calculating the Young's Modulus of Rubber - Calculation Check

    Homework Statement Dear Yahoo Answers, Can someone please help me with this as it's driving me crazy! We had to complete an experiment where had to calculate the Young’s modulus of Rubber, by doing an experiment. So we used a rubber band and various weights to calculate the values, to...
  6. M

    Phase transition of a rubber band model

    Homework Statement In class we studied a phase transition in a model of a rubber band. For small applied tensions, f < f^*, the Helmholtz free energy of the band as a function of the length is A_1(L) = (\kappa_1 /2)L^2, while at large applied tensions, f > f^*, it is A_2(L) = (\kappa_2 /2)L^2...
  7. M

    Thermodynamics - heat flow of a rubber band

    Homework Statement Consider a rubber band for which the tension, f, as a function of temperature T and length L is f = \kappa T (L+\gamma L^2), where \kappa and \gamma are positive constants. Determine the heat flow between it and its surroundings when the rubber band is stretched reversibly...
  8. U

    Is There a Known Process to Devulcanize and Revulcanize Rubber?

    Does there exist a known process to devulcanize rubber (i.e., getting out all the sulfur crosslinks from the polymer chains) and get out of the process rubber that can be revulcanized? Or does one big slash on a tire mean that 20-30 pounds of rubber can never be used for making tires again?
  9. S

    Produce harmless gas to inflate a rubber balloon

    Hi to all I am new to this forum. I need some help. I want a chemical reaction which produces a harmless gas with the use of small amount of reactants. Thanks Shashank
  10. S

    Rubber stopper hanging from the view view mirror of a car

    Homework Statement A 18g rubber stopper is suspended by a 45-cm string from the rear view mirror of a car. As the car accelerates eastward, the string makes an angle of 5.1 degrees with the vertical. Determine the acceleration of the car. Homework Equations The Attempt at a...
  11. G

    Velocity of wave along a rubber cord

    ]Homework Statement You have a rubber cord of relaxed length x. It be- haves according to Hooke's law with a "spring con- stant" equal to k. You then stretch the cord so it has a new length equal to 2x. a) Show that a wave will propagate along the cord with speed...
  12. J

    Distance traveled by a rubber band powered car

    okay guys I've been looking for ages and i just can't find anything that will help me with finding a distance that will be travel by a rubber band powered car. I've been playing around with kinetic energy= potential energy but i can't seem to get anywhere. Any help will be greatly appreciated...
  13. R

    Coefficient of Friction Wood on Rubber: Mu Value

    anyone know a value for the coefficient of friction of wood on rubber? rhys
  14. T

    Does a Pulled Air-Filled Rubber Ball Sink?

    If a rubber ball is fill with air, attached to a cord and pulled under water, I assumed it collapses under pressure at some rate. The question is, will it at some point lose enough bouyancy to sink to the bottom?
  15. G

    Impulse: Clay ball that sticks vs. Rubber ball that bounces?

    Homework Statement A 10 g rubber ball and a 10 g clay ball are thrown at a wall with equal speeds. The rubber ball bounces, the clay ball sticks. Which ball exerts a larger impulse on the wall? Homework Equations J (impulse) = Favg*dt The Attempt at a Solution I think that...
  16. I

    Why does a rubber band shrink when heated with a hairdryer?

    Hmm...some experimenting led to an interesting result. I attached a weight to a rubber band and suspended the rubber band in some hot water. The rubber band expanded. I repeated the experiment in cold water and the band shrank. An expected result, yes? Well I redid the experiment in air and I...
  17. J

    Calculating Energy Stored in a Twisted Rubber Band

    Hi, Not sure if I'm asking this in the right place, but I was wondering about the energy stored in a rubber band for a physics project I am working on. We all know that for a spring or rubber band being extended, the restoring force is given by F=-kx, and the energy stored U=0.5kx2. However...
  18. G

    Wave propagation along a rubber cord.

    Homework Statement You have a rubber cord of relaxed length x. It be- haves according to Hooke's law with a "spring con- stant" equal to k. You then stretch the cord so it has a new length equal to 2x. a) Show that a wave will propagate along the cord with speed...
  19. L

    How Does Temperature Affect the Heat Capacity of a Rubber Band?

    [b]1. The problem: Suppose a rubber band obeys the equation of state: L = f (b/T), where L is length, f is tension, b is a constant, and T is temperature. For this rubber band, determine (δC[SUB]L/δL)[SUB]T, i.e. the change in the constant length heat capacity with length at constant...
  20. T

    Rubber ball Rotational Motion Question

    Note: I refrained from using any of the latex references, so bear with me. Homework Statement A rubber ball with a radius of 3.2 cm rolls along the horizontal surface of a table with a constant linear speed v. When the ball rolls off the edge of the table, it falls 0.66 m to the floor below...
  21. K

    Rubber bullet / metal bullet hitting wooden block

    The bullet hits near the top of block. Which will tip the block over? Which will do most damage? I believe the rubber will tip it over and the metal will do the most damage...but I'm not sure how to explain it. When the metal hits it enters the block. When the rubber hits there is a...
  22. G

    Acceleration of 2 Rubber Bands on an Object

    Homework Statement Two rubber bands pulling on an object cause it to accelerate at 1.6 m/s2 (a) What will be the object's acceleration if it is pulled by six rubber bands? Answer: 4.8 m/s/s (correct) (b) What will be the acceleration of seven of these objects glued together if they are...
  23. A

    Quantization of Length: Can You Achieve Every Length Between 1" and 2"?

    Do I understand this?-if I stretch a rubber band from a 1" length to a 2" length... If I stretch a rubber band from a 1" length to a 2" length, is it true that it was not all possible lengths between 1" and 2" sometime during the stretch? In other words, at some level, quantization enters in...
  24. M

    Which one is more elastic: steel or rubber. and why?

    Hi, I want to know that which one is more elastic: steel or rubber. and why?
  25. N

    Foam rubber ball hanging in a string - Forces

    Homework Statement Okay, so I'm not originally an English speaker, so this may be silly reading for some of you, especially a lot of the words here, which isn't to find in the dictionaries either, but hopefully you'll at least get a picture of the task and help me solve it. The drag (air...
  26. M

    What is the static COF for rubber on steel?

    Hello all, im trying to find some data for the static COF for rubber on steel. I have been looking hard but can only find info for rubber on concrete and other non metals. I am doing the initial sums for a combat robot I am designing, but want to get the figures sorted out before i spend...
  27. P

    Rubber sheet analogy - density change

    When the rubber sheet with the bowling ball in it stretches, the density of the rubber is lowered as the rubber molecules become more widely separated by empty space. Are there particles of space time(?) that are similarily separated by more empty space when when the amount of nearby mass(?)...
  28. J

    Problem with Rubber and Metal Ball Analogy

    I'm struggling to understand how the stretched rubber & metal ball analogy explains the relativistic conception of gravity. It's possible that there is a simple and obvious solution to my confusion. It's also possible that this question has been answered many times. But I'll go ahead and ask...
  29. zoobyshoe

    Medical Adopting a Rubber Hand, and a New Twist on the Phantom Limb Phenomenon

    This indicates that sense of body position is arrived at by input from sight, touch, and proprioception, and that, when the stimuli are inconsistent, sight and touch are "believed" by the brain over proprioception: http://www.sciencedaily.com/releases/2004/07/040702093052.htm...
  30. E

    Why Does Rubber Create Sparks When Rubbed Against the Floor?

    Rubber is an insulator, so why does it make a spark upon friction with the floor? What would be a good material for shoe soles to avoid this problem?!
  31. P

    Rubber balloon in electric field

    Homework Statement A rubber balloon has a charge q evenly distributed over its surface. It is put into a uniform electric field of 120 N/C. What is the charge inside the balloon? Homework Equations The Attempt at a Solution I thought that E inside would be 120 since before it is...
  32. N

    Bowling ball rubber sheet analogy

    The typical rubber sheet bowling ball analogy to "explain" gravity visually in layman's terms always seems to be two space dimensions. Why don't we use one dimension of space and the other of time? Both are curved by mass and everybody takes Eucledean/Cartesian type flat graphs of, say, x and t...
  33. D

    Can I soften the rubber soles of my gym shoes to improve their grip?

    I have a pair of gym shoes that I really like, but because I have had them for about a year their bottoms have hardened up. They don't have very much grip anymore, and I'm wondering if there is some way to soften up their rubber soles. Is there something that they could be soaked in that would...
  34. M

    Rubber Ball response to impact?

    Please forgive my ignorance on what may be simple topics for most of you. I'm just trying to get my head conceptually around a ball launching pet project I'm fiddling with. If you take a rubber (tennis) ball, say of 5 oz mass, and blast it with a sprung plate moving at 70 mph, will the ball...
  35. K

    Rubber Band Model for 1D Chain of N Links

    In the text, there is a rubber band model for 1D chain of N links. Assume each link of the rubber band is align horizontally either to the right or to the left. In the text, define N_+ as the number of links directed to the right and N_- represents the number of links directed to the left. I...
  36. S

    Exploring Rubber Ink Filling: Which Method is Best

    Basic question - How does an rubber ink filler work? (I don't want answers like - there is a vacuum created thus ink fills space and thus... Thats not Physics) Extending discussion : Is it better to press the rubber then dip and then suck and remove. OR To dip then press and suck and remove?
  37. M

    Find the force applied to you by the rubber bands?

    Homework Statement A giant rubber band is going to launch you straight upwards. Upon launch your acceleration is 15 m/s^2 upwards. If your mass is 70 kg, find the force applied to you by the rubber bands. This is a copy word from word of the problem. Please be specific. I have a physics...
  38. G

    Ultimate tensile stress of rubber?

    Homework Statement How would you define the ultimate tensile stress of rubber? Homework Equations If I had a force/extension graph of rubber, what point in the graph would show me the value of the ultimate tensile stress?? The Attempt at a Solution Is it the same thing as ultimate...
  39. K

    Comparing Impulse in Collisions: Which Ball Experiences a Greater Magnitude?

    Homework Statement 2 equal mass balls (one red one blue) are dropped from the same height and rebound off the floor. the red ball rebounds to a higher position. which ball is subjected to the greater magnitude of impulse during its collision with the floor? a. it's impossible to tell...
  40. G

    Gonegahgah's rubber sheet example

    How close is this to what is being meant here? Let's say you have a big rubber sheet that can continue to stretch and stretch at the same rate and that it remains flat. (Yes a 2D analogy to help envision a 3D thing). On that sheet are little cars that move over the sheet. These cars...
  41. H

    Force / elastic potential energy of a rubber band

    Suppose we have a rubber band of some elasticity k and of unstreched radius r0 (the band is always kept in the shape of a circle). What work is necessary to strech it to some larger radius r? How do we apply Hooke's law in this situation? Thanks
  42. C

    Can a Toilet Plunger Break Glass?

    It's been a while since I've been in science class and I was wondering if this was theoretically possible. It's so specific because I'm writing a story using this scenario and now am wondering if it's completely unrealistic... What are your thoughts? Here's the question: Let's say you have a...
  43. S

    Momentum of rubber bullet problem

    Dear friends, If a bear's attacked by a: 1) Rubber bullet. 2) a lead bullet. Which'll be more effective in order to knock the bear down.I want to know how it's related to momentum phenomenon?I do know that lead bullet'll hit the bear down.Plz. reply in terms of momentum.Thanks.
  44. G

    Discover the Excitement of Rubber Bouncing Balls in Orbit - Shop Now!

    Is it possible to have many rubber bouncing balls (7?) and send it into orbit?
  45. D

    Exploring Trigger Mechanisms for Rubber Band Powered Vehicles

    I have a project that I'm working on involving a rubber band powered vehicle. I have a pretty well developed design involving several methods of propulsion but my main concern is a trigger mechanism in which to release this source of power from the rubber bands. Im not sure whether to go...
  46. O

    N.M.R. Comparasion of natural rubber vs synthetic rubber

    Homework Statement I'm trying to determine the difference between natural rubber and synthetic rubber using an undergraduate pulse-nmr machine... The graphs I obtained only show a difference in T2 time (shorter in the synthetic) but nothing else - but I'm supposed to "explain using my...
  47. Z

    Electric Force between glass ball and rubber ball

    Homework Statement What is the electric force between a glass ball with 3.5 µC of charge and a rubber ball with -5.0 µC of charge when they are separated by 5 cm? Homework Equations Colombs Law: F(electric)=K((q(1)*q(2))/r^2) K=8.99E9 The Attempt at a Solution This seems like a...
  48. E

    Rubber balloon is rubbed against a wall and then sticks to the wall

    Homework Statement A rubber balloon is rubbed against a wall and then sticks to the wall. This is because 2. multiple choice a. the balloon and the wall exchange charges through contact b. electrons hop back and forth between the balloon and the wall c. the balloon induces an...
  49. S

    Elasticity of metals springs and rubber bands

    How come both spring and rubber band are elastic whereas spring are contracted and rubber bands are stretched? I understand that elasticity of an object depends on it ability to reform from deform. I also get that spring works b/c of normal force(too much contraction...right?-being the reason...
  50. G

    How Can I Improve My Rubber Band Car to Reach 10 Meters?

    Rubber Band Car For Physics-- Any Help? I'm building a rubber band car for physics and need as much help as possible. I'm by myself this time because I chose (and regret it). But, so far I have found this much out: Stuff so far: *Records/CD's are good because of large Diameter *Heating...
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