Contact Definition and 448 Threads

Homework Statement A .1in aluminum wire is being pulled from a coil between 2 1in steel rollers. One roller is fixed to the driving motor while the other roller is loaded with a force to provide traction. What is the maximum force that can be applied before the wire is plastically deformed by...

As titled.This was taught to me in machine design, but I don't see how that makes sense I would think that doesn't matter how many teeths are in contact, since the force between gears are distributed on each pair of teeth in contact, more engaging teeth just mean the friction is distributed to...

If 3 masses are in contact with each other I understand that the acceleration is the same for all if a force is applied to the first mass. Is the net force on each object also the same? Assume no friction.

The four non-contact forces are explained with the help of different fields and their interactions. What about contact forces? Why does the door shut when I push it? Is it a simple transfer of momentum? If it is, do the electrons collide?

Hi all! I am trying to solve a transient contact analysis in Ansys 14.0 The problem is a Bouncing Rectangle problem. That's the procedure I use: /Prep7 k,1,-30,0,0 k,2,30,0,0 k,3,-30,30,0 k,4,0,30,0 Create->Areas->Arbitrary->Through Keypoints !Create the ground k,50,-20,30,0...

Hello, I have an arc with an arc length = 46.88 mm and radius = 44 mm. I have an intersecting arc with an arc length = 26.69 mm and radius = 43.4 mm. A circle with radius = 24 mm fits between the two arcs. How can I determine the contact points of the circle and the two arc lines?

Hi all, If I take an action involving two point particles coupled together by a delta function contact interaction is it possible to carry out the variation with respect to the fields? For e.g. S = \int dt \frac{1}{2} \dot{x}^{2} + \int \int dt \dot{x}(t) \delta^{D}\left(x(t) - y(t')\right)...

Assume that a box is motionless and is located on the floor ground (one box's face touches the floor completely). If we apply a force to this box such that the box keeps its motionless state, what we can say about the friction directions of all contact points between the box and the floor? Are...

Hi all, just want to ask is there any correlation between the contact angle of a anti reflective coating? i.e the bigger the angle, the better the anti reflective coating? Thanks in advance.

Homework Statement Two small charged objects of the same mass and volume are brought into brief contact with each other. If the initial charges on the two objects are -3.00 x10^-6 and -1.50 x10^-6, what is the electric force between the objects when they are separated to a distance of 0.500m...

What is the force of contact between the two blocks? Two blocks are in contact on a horizontal table. A force is applied on one of the blocks at a 30 degree angle (from the horizontal). The system moves towards the right. M1 = 2,00 kg and m2 = 1,00 km and F=60N and the kinetic friction between...

Hi, In general maintaining eye contact talking with people creates a sense of connection, but how do you feel about maintaining eye contact when listening to complex instructions? I often find it hard to maintain eye contact if an instructor is telling me something complex (such as...

in the picture below http://tinypic.com/view.php?pic=9riq9l&s=6 if we know the angular velocity of the gear on the left, as well as their current distance from contact point, what can we say about the velocity of the right rod at the contact point at anytime t? we know it is not...

Hello. I have an exercise (not exactly homework, it's a physics contest that we are allowed to solve at home, using all possible help we can find) that goes like this: A ball with mass m = 0,10 kg falls vertically on a horizontal non-movable solid surface. Speed of the ball just before the...

Can anyone explain point 44 of the attached pdf document on surface tension. (Here's the link in case attachment doesn't work: http://www.sakshieducation.com/EAMCET/QR/Physics/Jr%20Phy/12Surface%20tension%20_198-208_.pdf How is the surface tension direction found out? {i know it...

This is from my textbook: I'm slightly confused about the bit underlined in red. Do you think its in reference to the sentence just before where it talks about situations of vehicles remaining tangled? (so for other cases, contact time = impact time, right?) also, I don't really...

Homework Statement Two charged spheres are brought into physical contact with each other. Initially, the charge on the first sphere was 2.34 nC, while the charge on the second sphere was -3.23 nC. a) What is the final charge (in C)on either charge?(2A) b) How many electrons moved...

Hello, I have some doubts regarding the friction force on a certain situation. Imagine a disc over a fixed flat surface. Like this: The disc has two motions, rotational and translational but these are independent of each other. I mean the translational motion does not come from the...

Thank you for any help you are able to provide. I myself think that the electrons will flow to the human body and further drain the battery.

Can anyone explain point 44 of the attached pdf document on surface tension. (Here's the link in case attachment doesn't work: http://www.sakshieducation.com/EAMCET/QR/Physics/Jr%20Phy/12Surface%20tension%20_198-208_.pdf) How is the surface tension direction found out? Also why is...

my lecturer keeps saying that path of contact of an involute gear is straight line but without the reason. i can't digest it as i can't find the reason for this behaviour. I'm trying my best to find the reason. Internet too can't find an answer. Books don't give a timeline of how it happens. Can...

1. Homework Statement Three small identical metal spheres carry electric charges, +Q, +2Q, and +3Q. The centres of the spheres lie in a straight line at fixed positions R, S and T, such that the distance between the spheres at R and S is d1 and that between the spheres at S and T is d2. Assume...

Hi all! This isn't actually a homework question, but thought this subforum is the place for this anyway. It's been some ten years since I last touched the topic of mechanics and I guess this is a real simple question, but what can you do when I don't get it! Any help is appreciated! How do...

Hi! I am reading Molecular Driving Forces, 2nd ed., by Dill & Bromberg. On page 53, example 3.9, we consider why energy exchanges between two systems from the point of view of the 2nd law. We consider two separate systems. Each has ten particles, and each particle has two possible energy...

In rolling without slipping, why does the point of contact have zero velocity relative to the ground? If so, how can the point of contact move relatively to the ground? (It has to move relative to the ground, otherwise it cannot roll and must stay in its original position)

Hi everyone, I'm new to the forums and I don't have the knowledge you guys have about Physics, so my questions will be very simple. Yesterday I was reading a topic about using the antimatter as a weapon, and someone said it is impractical for many reasons, and he stated some, but only one got...

Homework Statement A small body is set on the surface of a smooth sphere at an angle of 45 degrees from the center. At this point the sphere is given a constant acceleration in the horizontal direction of 9.8 m/s/s. There is more in the question, but the goal is to find when the body will...

Hi there, I would like to know that if we have an leaning object supported by another object, both are supported by ground floor to satisfy static equilibrium condition, does the reaction force at the contact point produce cancelling torque (for the leaning object)? In general, can a reaction...

Homework Statement Three boxes are stacked, one on top of the other. The mass of the top box is 4kg. The mass of the middle box is 3.5kg. The mass of the bottom box is 3.0kg. What is the force exerted by the middle box on each of the other boxes? Homework Equations Fg = mg The Attempt at a...

Cranial Nerves: The cephalic level of contact with the CNS...? Homework Statement I am having to list off the 12 pairs of cranial nerves.. But, I also have to list the following for each one. "The cephalic level of contact with the CNS (eg. telencephalon) where the nerves nuclei are...

This is a paradox that has been bothering me since I was taking algebra in high school. Let's say that I want to represent the distance between to objects. Given that numbers are infinite in both directions, by which I mean that there is no limit to how large, or small a number can be, there...

Homework Statement Two blocks of masses m1 and m2, with m1 > m2, are placed in contact with each other on a frictionless, horizontal surface. A constant horizontal force is applies to m1. a) find the magnitude of the acceleration b) determine the magnitude of the contact force between the...

Homework Statement In an experiment to determine how well benzene wets glass, benzene was found to rise to 1.71 mm in a certain capillary tube at 20.0 C. In the same tube, water rose 4.90 mm at 20.0 C. Calculate the contact angle for benzene, give that at 20.0 C, benzene = 0.879 gcm^-3...

Homework Statement If you have a system with three boxes, two side by side and one on top of the first box and there is a horizontal force acting on the boxes, do you have to account for the third box in calculating the contact force between two of them? Say if box 1, box 2, and box 3 (three...

Hi, I am trying to understand a theoretical problem involving the contact between two surfaces. I have uploaded a screen shot of the mathematical formulations of the solution. I understand most of the solution, except the principal curvatures. I have tried to look up principal curvature...

Hi all, I am currently working to build a Joule Heater that will be used to heat samples to upwards of 1000*C in seconds in vacuum. While the temperature and speed is definitely there, the contacts are always non-uniform -- making the data hardly repeatable. I am using a ~70mmx10mm Silicon...

hey i had a bizarre thought, what if there is a road made with a very smooth friction less surface and a normal asphalt road, arranged alternatively, such that , half the time spend by the tire in one rotation is placed on the smooth side and the other half on the rough side, such that the tire...

Hello, I've been having trouble with a certain part of a homework problem. I wish I had posted this earlier so there would be more time! Anyway... The shape is a semi-ellipsoid (a Rattleback, in particular). Here's a good picture of what I'm talking...

Trying to model a thermal contact between two faces. The plan is to get the heat flowing from the right part to the left part with a temperature BC on the right and convection on the left. At the moment the left part stays in the initial temperature so the contact obviously doesn't work. I...

I am asking my mentor for my class about this question, but unfortunately the answers I get from her often take forever and do not always clear things up for me, so I hope someone out there in Physics Forum has a good way of explaining this to me. Here goes... The question has some...

When ever I go trying to solve a problem, especially the ones that have my mind greatly diverge into many concepts, I seem to notice myself losing contact with logic. Its like a bad dream really. I find myself attempting to solve how I am solving a problem and so on. Or at least questioning what...

Homework Statement See attachment Homework Equations The Attempt at a Solution Ok so as the bridge is at a point ABOVE eqm acceleration is DOWN and at some point ACC down is greater than gravity acceleration. This is all true but makes no sense to logically. How could the car...

I have been working on a slightly tricky calculus problem and was hoping someone could verify my solution. Homework Statement A 4m long beam whose mass is 5 kg is attached to the wall by a wire and a hinge that allows the beam to rotate. There is a sign (with a mass of 20 kg) attached to...

Hi, My name is Rupak Karnik. I am currently a third year student in electronics engineering in Mumbai, India. I have a very keen interest in astrophysics and space sciences and I plan to pursue a career in the same. I have a mid-semester break during the months of June and July for 6 weeks...

Homework Statement The following is a worked problem from my textbook: Consider two masses, with initial tempratures T1 and T2 are placed in contact and isolated from their surroundings. They are CV1T1 + CV2T2 = CV1Tf+CV2Tf This equation can be solved for the final temprature T_f =...

Contact surface -- term Hello everyone! Help me please with selecting a correct term. The situation is as follows: There is a valve, which has a body and a bonnet. There is a joint that connects the body to the bonnet. There is a contacting surface on the bonnet flange and body flange...

Dear All, When an electrical contact is made onto the quantum well, how would the energy states be affected ?

The potential at which a metal is deposited in the electrowinning process can significantly affect the quality of the deposit. The potential itself can be dramatically affected by the addition of complexing agents and by adjusting the pH of the solution as the following calculations demonstrate...

Two soap bubbles of radius r and R are in touch find the radius of curvature of their point of contact? (Both bubbles are touching each other with their external surfaces) I have no idea about this question. can you please try to help>

\frac{x[Ain]-x[Aout][/SUB][/SUB]}{x[Ain]-x[out][/SUB][/SUB]}=\frac{\sum s^{K}-1}{\sum s^K} (1) for k = 0 to n Final result...