Elastic fibers (or yellow fibers) are an essential component of the extracellular matrix composed of bundles of proteins (elastin) which are produced by a number of different cell types including fibroblasts, endothelial, smooth muscle, and airway epithelial cells. These fibers are able to stretch many times their length, and snap back to their original length when relaxed without loss of energy. Elastic fibers include elastin, elaunin and oxytalan.
Elastic tissue is classified as "connective tissue proper".Elastic fibers are formed via elastogenesis, a highly complex process involving several key proteins including fibulin-4, fibulin-5, latent transforming growth factor β binding protein 4, and microfibril associated protein 4 In this process tropoelastin, the soluble monomeric precursor to elastic fibers is produced by elastogenic cells and chaperoned to the cell surface. Following excretion from the cell, tropoelastin self associates into ~200 nm particles by coacervation, an entropically driven process involving interactions between tropoelastin's hydrophobic domains, which is mediated by glycosaminoglycans, heparan, and other molecules. These particles then fuse to give rise to 1-2 micron spherules which continue to grow as they move down from the cells surface before being deposited onto fibrillin microfibrillar scaffolds.Following deposition onto microfibrils tropoelastin is insolubilized via extensive crosslinking by members of the lysyl oxidase and lysyl oxidase like family of copper-dependent amine oxidases into amorphous elastin, a highly resilient, insoluble polymer that is metabolically stable over a human lifespan. These two families of enzymes react with the many lysine residues present in tropoelastin to form reactive aldehydes and allysine via oxidative deamination.These reactive aldehydes and allysines can react with other lysine and allysine residues to form desmosine, isodesmosine, and a number of other polyfunctional crosslinks that join surrounding molecules of tropoelastin into an extensively crosslinked elastin matrix. This process creates a diverse array of intramolecular and intermolecular crosslinks These unique crosslinks are responsible for elastin's durability and persistence. Maintenance of crosslinked elastin is carried out by a number of proteins including lysyl oxidase-like 1 protein.Mature elastic fibers consist of an amorphous elastin core surrounded by a glycosaminoglycans, heparan sulphate, and number of other proteins such as microfibrillar-associated glycoproteins, fibrillin, fibullin, and the elastin receptor.
Homework Statement
Consider a pool table that contains two identical balls. Ball 1 is rolling at a speed of 1.1 m/sec when it hits ball 2 which is at rest. The coefficients of friction between the balls and the table are 0.8 (potential) and .5 (kinetic). The collision is perfectly elastic...
Homework Statement
I'm completing a homework for Young's Modulus and one question asks to estimate the elastic limit for the wire which was used.
I can see where this approximately is on the graph I have drawn. When the question asks to estimate the elastic limit, does this mean to...
say i derive the relationship between the 3 elastic modulii for a sphere.
i consider the 3 co-ordinate axes.if stress is applied only along x-axis,there would be a resulting strain along Y and Z.
My book derived it for a cube,that was quite simple,but i cannot imagine the resulting strain...
When two objects collide in an elastic collision, aren't there an infinite number of possible velocities that the objects can gain? Let's consider two objects each of mass 1kg. One of them is moving at 1 ms-1 and the other is stationary.
After the collision, the first object (the one which was...
NONElastic Collision
Homework Statement
One sphere collides with other sphere that has speed of u2 = 0... Both spheres have same mass (m1 = m2 = 0.3 kg)... After collision first sphere has speed of v1 = 0.6 m/s, second sphere v2 = 1.1 m/s ... How much of kinetic energy has been transformed...
Homework Statement
A uniform rectangular tile drops without spinning until its corners reach positions
(0; 0; 0); (2a; 0; 0); (2a; 2b; 0); (0; 2b; 0), when it strikes the top of a vertical pole at a
point very close to the (0; 0; 0) corner. Just before impact the velocity of the tile was...
Let' say two steel or rubber disks hit each other
moving on friction-free surface.
During the interaction, both disks deform elastically.
My question is, does part of deforming energy
gets converted to heat ?
Why not ? Why this effect is never mentioned ? Is it negligible ?
I know from...
Homework Statement
First sphere m=0.3 kg collide noncentraly and elasticaly with other sphere of m= 0.35 kg and transfer 79% of first sphere kinetic energy during that collision... u1 is not defined, u2 = 0 m/s
Ratio between speed after collision v1 : v2 = ??
Homework Equations...
Good afternoon,
First of all, this is not a homework question, but I'm not sure whether it should be posted on the Homework section.
My problem arose when I tried to think about what happens when a spring does work in two blocks.
First, consider two blocks (1 and 2) on a frictionless...
Thinking in terms of the conservation of energy, it seems to make sense that if you took a relatively elastic rod with hooks on either end, so that it could be bent all the way around and made to hook to itself (and make a loop), that the energy required to bend it into a closed loop would be...
Homework Statement
I am unsure about how to go about solving an oblique elastic collision question, I understand that momentum is conserved and how to calculate momentum but unsure as to how to calculate the vectors.
The question is : A 45g marble collides with an identical stationary...
Incidentally in another thread I made this reasoning to calculate the velocity increase in an elastic collision:
My questions:
(a) I haven't seen this approach in the texts I use. Is this correct? Am I missing anything?
(b) If correct, is it also valid for acceleration, not only for...
Homework Statement
A mass of 1.5 kg oscillates vertically at the end of a lightweight spring. The spring has a spring constant of 145 Newtons per meter. The amplitude of the motion is 8.00 cm. From this data, complete the table below.
I have to find velocity, acceleration, elastic...
Homework Statement
Uranium fission within a nuclear reactor produces high-speed neutrons. These must be slowed down for them to trigger a chain reaction within the uranium. In a heavy-water reactor the neutrons of mass m make multiple elastic collisions with deuterium nuclei of 2m, losing...
Here's the problem I've been working on:
"A mass is oscillating with amplitude A at the end of a spring. How far (in terms of A) is this mass from the equilibrium position of the spring when the elastic potential energy equals the kinetic energy?"
Now I know that Us = 0.5*k*x^2 and K =...
I'm given a stress strain diagram for a sample of steel that has an original diameter of 0.5in and a gauge length of 2in. The sample is loaded to 70ksi and the question asks for the amount of elastic recovery and permanent elongation of the sample. The actual graph is shown below...
I know...
Hello everybody,
I am having some troubles with this exercise. I have attached the text and the solutions to my post. My problem is, after I have coupled the angular momenta and used the CK coefficients like in (|\pi ^{+}p>=|1,1>|1/2, 1/2>=|3/2,3/2>) (pag.432) I don't understand what...
1. A mass of 100g is suspended from a light spring and extends the spring by 4cm when the mass in in equilibrium.
a) Find the spring constant k of the spring?
b) How much elastic energy is now stored in the spring?
c) What would be the extension of the spring if a mass of 170g were suspended...
I'm inputing data into a SolidWorks material profile, but I'm having difficulty determining the value of the elastic modulus (psi) of steel reinforced concrete
i'm looking at the following source for material properties:
http://www.fhwa.dot.gov/pavement/pccp/pubs/05081/chapt3.cfm [for...
Homework Statement
After some messey algebra it can be said that
V_B = (2 m_A V_o_A)/(m_A + m_B)
V_A = ( (M_A - M_B ) V_o_A )/(M_A + M_B)
were did this come from?
Homework Equations
momentum
The Attempt at a Solution
I don't even know were to start
Just to begin, uhh. I'm 75% sure my work makes logical sense [I hope], and that my problem lies in a computational error. But I really don't know why my answers aren't working out. I've now gone through the problem in 3 different ways, and I keep getting the same answer, but it's apparently...
Homework Statement
Suppose that the string in fig 8-12 (just a pendulum released from the side and falls to the bottom) is very elastic, made of rubber, say, and that the string is unextended at length l when the ball is released.
a) explain why you would expect the ball to reach a low...
I've tried looking on various websites to find a definition I can understand but every website describes it differently, even the online dictionaries. I have also tried looking in my Y&F University Physics. I just don't <i>understand</i> what elastic hysteresis is because most descriptions don't...
Homework Statement
Onto a thick brass rod we attach equally long glass thread. At what temperature change will the glass thread break if the temperature coefficient of linear expansion for brass is
α1= 20 x 10 ^-6 K^-1, and for glass is α2= 7 x 10^-6 K^-1? Young’s (elastic) modulus for glass...
Homework Statement
Onto a thick brass rod we attach equally long glass thread. At what temperature change will the glass thread break if the temperature coefficient of linear expansion for brass is
α1= 20 x 10 ^-6 K^-1, and for glass is α2= 7 x 10^-6 K^-1? Young’s (elastic) modulus for...
Elastic collision, I think?
Homework Statement 50kg boulder slides down a 5m high, 20m long hill against friction force 40N. At the top the boulder is moving at 2m/s. At the base of hill the boulder slides on a horizontal frictionless surface for a short distance and then collides with a tree...
Homework Statement
.500kg ball attached to a cord that is 70 cm long. ball strikes a 2.5kg block at rest
what is the speed of the ball just before hitting the block
and collison is perfectly elastic find speed of ball and block after collision
Homework Equations
The Attempt at...
Homework Statement
A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 41° from the neutron's initial direction. The neutron's initial speed is 6.2 x10^5 m/s...
Hey there! So, I've got this sample exam that I'm working my way through, and I'm stuck on a few questions, but this one is particularly frustrating me:
A careless driver rear-ends a car that is stopped at an intersection. Just before the collision, the driver slams on his brakes, locking the...
Homework Statement
A 29.0 g ball is fired horizontally with initial speed v0 toward a 100 g ball that is hanging motionless from a 1.10 m-long string. The balls undergo a head-on, perfectly elastic collision, after which the 100 g ball swings out to a maximum angle θmax = 50.0°
see image for...
Question:
Is more elastic potential energy stored in a spring when the spring is compressed by one centimeter than when it is stretched by the same amount?
my conclusion:
part of the definition in the book states that Elastic Potential Energy is the energy that a spring has by virtue...
SOLVED
Homework Statement
A 120g granite cube slides down a 40 degree frictionless ramp. At the bottom, just as it exits onto a horizontal table, it collides with a 225g steel cube at rest. How high above the table should the granite cube be released to give the steel cube a speed of...
Homework Statement
A 47.0g ball is fired horizontally with initial speed (Vo) toward a 110g ball that is hanging motionless from a 1.00m -long string. The balls undergo a head-on, perfectly elastic collision, after which the 110g ball swings out to a maximum angle theta = 52.0 degrees.
What...
One ball traveling at 17.7 m/s strikes a second ball at rest in an elastic collision. If the mass of the first ball is 30 kg and the mass of the second is 1.2 kg, to the nearest tenth of a m/s what is the velocity of the first ball after the collision?
Homework Equations
Homework Statement
I can't believe I cannot get this! I am trying to help out my gf with this problem:
A 5 kg ball moving at 2 m/s to the right collides with a 7.5 kg stationary ball. If the collision is elastic, what are the final velocities of the 2 balls?
Homework Equations...
Homework Statement
A pinball machine launches a 90g ball with a spring driven plunger. The game board is inclined at an angle of 6\circ above the horizontal.
Assume the plunger's mass and frictional effects are negligible. The acceleration of gravity is 9.8m/s2.
Find the force...
Homework Statement
Suppose you have a mass/spring system (with spring constant k) buried underground such that its relaxed (equilibrium) position is level with the ground. Then suppose someone takes a small ball of mass m and compresses the spring a distance xo below the mass/spring's...
Homework Statement
A 120 g ball moving to the right at 4.5 m/s catches up and collides with a 420 g ball that is moving to the right at 1.2 m/s.
If the collision is perfectly elastic, what is the speed of the 420 g ball after the collision?
Homework Equations
m_1v_{1i}+}m_2v_{2i} =...
I am struggling with a problem that I could really use some assistance on. The problem sounds simple enough, but I am lost. here it is:
Block A is on a frictionless table with block B. Block B is at rest, block A heads toward B and collides in an elastic collision. Block B falls off of...
I feel so confused right now, I'm probably over thinking this though. Please help!
1) A slingshot consists of a light leather cup, containing a stone, that is pulled back against two parallel rubber bands. It takes a force of 11 N to stretch either one of these bands 1.1 cm.
(a) What is the...
Homework Statement
Particle 1 of mass m moving with speed v in the +x direction has an elastic
collision with particle 2 of mass 3m which was originally at rest. After the collision,
particle 2 is moving in the +x direction. What is its speed?
Homework Equations
deltap = 0
pf1 + pf2 =...
Homework Statement
The setup is there are two pucks (m1, m2) on an air table and they undergo elastic collision while m2 is stationary. I am asked to find the angle between the two velocities but I can't figure out how without being giving at least one angle.
Variables:
m1 = 28.0 g = 0.28...
Homework Statement
I am basically being asked to use the law of conservation of momentum and kinetic energy to derive two equations for the final velocity of the two masses involved in the system. (i.e. \acute{v_{1}} and \acute{v_{2}})
Homework Equations
Conservation of Momentum...
Homework Statement
A rapidly moving body of mass m1 strikes a body of mass m2 at rest in a head-on elastic collision. How does m1 compare with m2 if the first body (m1)
a. stops?
b. comes back along its path at very nearly the same speed it had before the collision?
c. continues along in...
[SOLVED] Elastic and gravitational potential energy
First off, long time lurker here on his first post. Your forum seems absolutely brilliant, so I hope you can help me :)
Homework Statement
A box on an elastic string is dropped down an incline and proceeds to slide the distance L before...
Homework Statement
Consider a hollow drive shaft of length L, inner radius b, outer radius a. A constant torque is applied (we can assume one end of the shaft is fixed because we're applying a constant torque T regardless of the angular velocity of the shaft). We know material properties of the...
Hi guys,
I was thinking of a problem the other day; consider a group of particles, connected to each other by light elastic strings, there is no restriction on which particles can be connected to which, then can one determine the position of a particle at time t.
So I set about trying to...
Homework Statement
A 20g ball is fired horizontally with initial speed vi toward a 100g ball that is hanging motionless from a 1.0m long string. The balls undergo a head-on, perfectly elastic collision after which the 100g ball swings out to a maximum angle of 50degrees. What was vi...
Homework Statement
In a pool game, the cue ball, which has an initial speed of 8.0 m/s, make an elastic collision with the eight ball, which is initially at rest. After the collision, the eight ball moves at an angle of 30° to the original direction of the cue ball.
Homework Equations
V8...