Contact Definition and 448 Threads

A cylinde with a piston in contact with a heat reservoir at 353 k. While keeping this gas at constant temp and pressure of 1.01 x 10E5 n/m2 we permit he gas to expand by 1.5E-5 m3. How much heat does the gas absorb? Is it just p x v = w and w = q to get an answer of 1.15 j? Cause i feel like...

I have calculated a static contact stress of 670 N/mm2 using formula from Mechanical Engineering Design, Shigley, 5th Edition. My problems lies that there is no acceptance criteria. I'm using Grade 5 Structural Steel (yield~355 N/mm2). Previous threads have stated that a 2.5 * yield can...

Hi I was just wondering what ways you can smash glass without physically touching/breaking/throwing something at it. For example, I know that the "force" of an explosion can break glass that is a fair distance away from the actual explosion. So is there any way you could make something that...

Hi this is a problem from my midterm at the beginning of the quarter and i have a final coming up so i need to know the previous midterm material but i still don't understand this one question. Dave suddenly drops from the wire and lands at a velocity of 2m/s on some cardboard boxes that...

For my Project, two angular contact bearings are selected to support a spindle. However, I would like to preload both the bearings considering thermla expansion.. I would like to know the max. permissible preloading limits for the bearings. Could someone suggest me some good material or links to...

Hi all, I'm using ABAQUS to do a bit of material modelling. I don't have concrete understanding of this but I'll explain what I am trying to do: Essentially a piezoelectric and a metal in contact under strain. The piezoelectric produces an electric potential which I hope can be...

My teacher said there isn't a special kind of formula, you just derive it from f=ma. This is the diagram:

Homework Statement A nearsighted person has near and far points of 11.0 and 22.0 cm , respectively. If she puts on contact lenses with power P = -4.00 D, what are her new near and far points? Homework Equations P=1/f 1/f=1/do+1/di where f=focal point, do=distance to object...

hello all I have this problem to solve in ansys workbench 13 (Im new to this software): two parallel 5000mm length square beams in contact 200x80x8 (EN10219: structural hollow sections ) in frictionless contact and on the sides two side plates. At the ends I have two suports and I have on top...

What happens when two objects of different charges come into contact? Do they distribute the charges per mass, volume, surface area or something else?

"If there's no normal force, there's no contact." Is the statement above correct? What is the relationship between contact and the existence of normal force? Are they necessary and sufficient conditions to each other? Thanks for your help :p

1. What happens when two spinning disks collide? Suppose you have two flat, thin disks with uniformly distributed masses m1 and m2, moving at angular velocities ω1 and ω2. the two objects are brought together edge to edge, ie they collide. obviously as a result of this collision, the objects'...

Homework Statement "Consider three magnetic systems in thermal contact, each composed of N1, N2, N3 spins, +m or -m. Starting from s1 = s'1 + δ1 etc. calculate the average square deviation <si2 of each system. Homework Equations s'1 is the most probable configuration for s1. N1+N2+N3 =...

Hi All I recently purchased a 1000w heating element for coffee cups, http://www.ebay.com.au/itm/110668421004 that I will be using on a 240v AC source. I would like to know if a cup out of silicone will withstand direct contact with the element? From what I am reading normal silicone...

Hello! I know that the contact force formula is Fc = F(m2/(m1+m2)) but I was wondering, how did this equation come into being? How is it derived? No this is not a homework question, I was just curious to know. Thanks!

Homework Statement A 0.25 kg ball, initially at rest, is hit with a bat in the x-direction while held 1.00 meter above the ground. If the ball hits the ground 20 meters away and was in contact with the bat for 0.10 sec, What average force was exerted on the ball during the contact time...

Homework Statement A force of magnitude 7.50N pushes three boxes with masses m1=1.3kg, m2=3.2kg, and m3= 4.9kg as shown in the figure. I want to find the magnitude of the contact forces between boxes 1 and 2, and between boxes 2, and 3. Now, the force, 7.5N is being pushed from right to...

How to find out contact time of 2 Carrom men in carrom board game? I am trying to develop a game of carrom board. For this i want to know how to find contact time if Co-efficient of restitution and velocities before contact is known?

I guess point A is the origin of my stationary axis, with Y going up along AB, then X going along AC. My moving axes would be at the center of the moving disk at point C. So, the w of the small disk is induced by the Ω of the main shaft along AB. If the radius of the small wheel is r, then...

led chips is a P-N jontion which MQW in middle. And than it bonds metal on P-side and N-side which we call ohmic contact.I had try to draw the band gap graph. Base on theory, when different material bond together, their fermi energy became the the same energy level. I know that the contact of...

I know theoretically that friction is independant of contact area. However, i have a cylinder which i want to clamp via two jaws. My thinking is that a v jaw, clamping at four points around the circumference of the cylinder would be more effective than a curved jaw design?? Thoughts would be...

Hi I am having a little trouble designing a micropump out of a mini dc motor-it needs to be able to extract small amounts of liquid (approximately 50 microliters) through a small tube (diameter 0.2 cm or 2 mm) without having the liquid pass through it. Is there any way I can use the motor to...

Homework Statement A small smooth ring R, of mass 0.6 kg, is threaded on a light inextensible string. One end of the string is attached to the fixed point A and the other end is attached to a ring B, of mass 0.2 kg, which is threaded on a fixed rough horizontal wire which passes through A...

I'm trying to determine the contact surface area of a threaded bolt so that I can make some changes to the design and maintain the same contact surface so as not to affect the performace in other ways. This presents itself as a helix, and my initial guess was that it may be best to work this...

Hi, Just have a few questions about this chapter if anyone here is familiar with it... 1) Does anyone know why the k^2_i \to -m^2 limit is imposed in (67.4), is it just because he wants external particles to be physical and hence on-shell? I derived this equation from the one directly above...

considering this relay http://my.element14.com/durakool/dm84-2012-35-5024/power-relay-dpdt-2co-24vac-8a-pc/dp/1557207" what does contact DC voltage meant? and to energize / activate the coil i need a 24v current to do the job?

Hello All, I am facing some problem while defining contact between shell elements. My problem is as below. 1. Two thin layers (thickness of 10^-5 m each) of composite material are bonded to a solid material like foam. 2. A third layer of the same thickness comes in contact for a certain...

hi.. This is abdul I am carrying a impact of sphere on a composite laminated plate. i wanted to calculate the contact force when sphere impacts the plate.. or can anyone help me how to get the stiffness of plate.. or deflections in plate.. with respect to time Thanking you Your help will...

Hello everyone! I am struggling with calculating the normal forces for a vehicle that is in contact with the ground at three places (scoop, front wheels, rare wheels). To calculate the normal forces with two locations (such as front and rare wheel) it is just to balance the forces as well...

Hi All, I am trying to get an analytical solution to a contact problem with dynamic loading. I am not sure if an analytical solution of such a problem is possible. Here how the problem is: A cantilever beam, with its free end resting on a smooth plane, is under harmonic loading f(t)...

Hi, I am trying to do a vibration analysis of a cantilever beam in contact with Earth (in ABAQUS). Now I need to match these results with the analytiocal solution. Could any of you guide me any paper or book where this klind of a problem is solved. So basically I am looking for the...

Simulating "Bonded Contact" from ANSYS Mechanical in ANSYS APDL Hi, Im looking into the accuracy of using different element types to model a particular structure. As a simple approximation think of it as a beam split into 3 horizontal sections. Shown in the diagram as top, middle & bottom...

Do I believe there is life elsewhere in the cosmos? Absolutely. Do I think they have radio, nuclear fission, space-faring vessels and maybe even technology far beyond our comprehension? Yes, but they are likely so rare, it's inconceivable that we will ever cross paths. Why? For...

Does gravity stop accelerating objects once they are in contact with Earth's surface? If so, why?

Homework Statement After some digging, you locate your aluminum baseball bat (1.3 kg, c = 0.90 kJ/KgK) in a snowbank(0 Celsius) and bring it into a warm (25 Celsius) room. If the 64 m^3 room contains 76 kg of air (c = 1.02 kJ/KgK) and no one goes in or out of the (closed) room, what is the...

Homework Statement A uniform plank of length L leans against a vertical wall, its head a distance h above the horizontal ground. If we let go of the plank from rest, how far above the ground is the head of the plank the moment it loses contact with the wall? Homework Equations Fx=0 Fy=mgThe...

So I was talking with my physics professor a while back about how friction force in a tire is independent of how much of the tire is in contact with the road. ie: Mu*(m*g) doesn't take into consideration the size of contact area and the friction is the same because essentially the weight (m*g)...

Hello all! I'm modeling with ANSYS 12 (workbench) an assembly made up by components which are initially in "gap" condition, going in contact after deformation due to the applied pressure load. I tried in a "static structural" analysis by settings the manual contact regions type "frictionless"...

Homework Statement Two blocks are in contact on a frictionless, horizontal tabletop. An external force, F, is applied to block 1, and the two blocks are moving with a constant acceleration a = 2.45 m/s^2. Homework Equations what is the contact force between the blocks? The Attempt...

1. Problem statement I've already posted this question in the advanced calculus help but it was suggested that I ask this in the physics forum. I can upload the pdf of my work again so I'll link to it https://www.physicsforums.com/attachment.php?attachmentid=31702&d=1296270924" from my other...

1.Two homogeneous rods have the same cross section, specific heat c, and density \rho but different heat conductivities \kappa1 and \kappa2. Let kj=\kappaj/(c\rho) be their diffusion constants. They are welded together so that the temperature u and the heat flux \kappaux at the weld are...

For the equation: contact stress = {(1 / (pi[((1-v1^2)/E1)) + ((1-v2^2)/E2))) ^ 0.5} * {((Fn/b) * (Sum (1/pi)))^0.5} Where Sum (1/pi) = [(1/p1) - (1/p2)] for concave shapes in contact with convex shapes Sum (1/pi) approaches 0 as the two radii get closer, however when the two radii...

Homework Statement Before hanging new William Morris wallpaper in her bedroom, Brenda sanded the walls lightly to smooth out some irregularities on the surface. The sanding block weighs 2.0N and Brenda pushes on it with a force of 3.0N at an angle of 30.0 degrees with respect to the vertical...

Homework Statement Hello, I am currently working on a robotics project that consists of building a self-balancing robot on a rotating cylinder. I am allowed a total surface contact area of 5 cm^2, and am currently wondering how to calculate the contact area of a whell on a surface (or curved...

Hi, I am going to contact a professor and ask him about the possibility for him to supervise me for the master degree. (Yes, we do masters first before PhD) But I have some important questions. Since this professor is from a different school of mine, I have never met or contacted him...

Homework Statement Three boxes rest side-by-side on a smooth horizontal floor. Their masses are 1.45 kg, 3.10 kg, and 5.20 kg, with the 3.10 kg one in the center. A horizontal force of 24.0 N pushes on the 1.45 kg mass which pushes against the other two masses. What is the contact force...

Homework Statement The Figure shows an approximate representation of the contact force versus time during the collision of a 42-g tennis ball with a wall. The initial velocity of the ball is 35 m/s perpendicular to the wall; it rebounds with the same speed, also perpendicular to the wall...

I see this all the time in job applications, including for the current employer section. Does it hurt your chances when you tell them not to contact them? I can understand that for former employees it'll signify that "I got fired" or "I torched bridges". I don't want my current employer to...

I came across a question in which a cubical body of mass 'm', edge 'a' is slipping down an inclination with constant velocity and torque due to normal contact force is to be found about the centre of the block. As friction will exert an anticlockwise torque= 0.5amgsinx, where 'x' is the...

Correct? Please let me know if my logic is off. =] Given Problem As shown in the figure, a force of magnitude 7.50N pushes three boxes with masses m1 = 1.30 kg m2 = 3.20 kg m3 = 4.30 kg (a) Find the magnitude of the contact force between boxes 1 and 2. (?N) (b) Find the magnitude...