Support Definition and 370 Threads

Do genetics and fossil record support the idea of genetic equidistance with respect to molecular clock, or is it mostly theoretical and inferred?

Hello every one I am confused between two support type: the pin, and the link On the textbook, it says, the pin prevents the object from translating vertically and horzontally, therefore, it provides fx and fy reaction forces. but another type of support is much identical to the pin...

Because of size constraints in my room, I need a platform for my queen size bed that is the exact footprint of the bed (60" x 80"). I've decided to attempt to build it however I have no experience with this and hopefully someone can point out any flaws in my plans. I've attached an image...

Here is a link to the problem: http://img62.imageshack.us/img62/374/frameow.jpg" I am trying to find the support reactions at A and B. I separated the frame at the hinge(call it C) into two parts and took the moment equation about point A. This gave me: \SigmaMa = -60(25) - 62.5(12.5) +...

Please help Due in 2 hours. Statics machine equilibrium: reactions- too many unknowns Homework Statement The woman using the lat pulldown machine is holding the 80-lb weight stationary in the position shown. What are the reactions at the built-in support E and pin support F? (A and C are...

Homework Statement The mass of the homogeneous flat plate is 50 kg. Determine the reactions at the supports A and B. I've attached the diagram. The Attempt at a Solution I know I will need to find the center of mass. I don't remember exactly how to do it, but I found the centroid...

Homework Statement The 8kg slender bar is released from rest in the horizontal position. When it has fallen 45 degrees, what are the x and y components of force exerted on the bar by the pin support A? Homework Equations F=ma where a= a t_hatt + v^2/p n_hat sin(45)=cos(45)=1/sqrt(2)...

"Support Ticket" Application/Plugin I work for a (very) small, private company. I'm trying to come up with a system that will allow those of us on the support staff to "claim" an email when it arrives so that we aren't troubleshooting the same equipment and stepping on each other's toes. We...

uniformly distributed load on a beam. it has a single simple support at the center of gravity. Beam length L and load distribution w (pounds/inch) How do I find the shear and moment diagrams?

Hi, I am stuck on this question... A student(850 N) sits on a 2 m long bench that weighs 625 N. The student is sitting 0.40 m from the right end of the bench. What upward force is exerted by the right support leg of the bench? please help! My attempt: (0.40m)(820N)+(1m)(625N) =...

Hi guys! How can one calculate your reactions at both ends of a simply supported beam if one reaction is higher than the other one? Example: Support A (one end of the beam) is 100mm higher than Support B (other end) and there is a 22kN/m UDL distributed along the length of 2.5m Does your...

Homework Statement Ok so I have a beam with the forces shown below. There is a 3 m span between the supports (A&B) and both of the supports are 1.5 m from the end of the beam. The 60 lb force is .75 meters left of support A and .75 m from the left end of the beam. P is an unknown force...

I got the algorithm to deal with every section profile. The software would calculate the area and the moment of inertia of any section or any combination of sections in different materials. Further more, I would develop it to deal with non-linear analysis finding the stress and strain on every...

Hello all, There is a 600 foot long asphalt pipeline that spans over a very large field. This specific pipeline is 10 inches in diameter and has a 3in diameter pipe attached to it. In addition, this pipeline as a whole is wrapped in 2 inches of fiberglass insulation. I need to figure out an...

hello! My first post here. I am by no means a mechanical engineer as I studied computer science in college. My question has to do with adding what is known as a cold air intake onto my vehicle. The design of the intake is such that the pipe fits at the throttle body via a silicone/rubber...

What do ya'll make of this: http://www.newscientist.com/article/dn20600-quantum-magic-trick-shows-reality-is-what-you-make-it.html "It appears that you can't even conceive of a theory where specific observables would have definite values that are independent of the other things you...

Hello all, I am currently working on a project which entails the following: There is a steel fence which is welded to steel sheet pile which is slowly beginning to collapse; much similar to that of the "Leaning Tower of Pisa". The sheet pile is driven 12 feet into the ground and the fence...

the support of a function is defined as the closure of the set where f is nonzero my question is why not just define the support as the set where f is nonzero? thanks

In this context, the support mapping of any convex geometry is any point on the geometry which results in the largest dot product to some direction vector. I would appreciate some help in computationally finding the support mapping of an arbitrary ellipsoid (some arbitrary orthonormal basis...

Homework Statement If X is a Poisson random variable with \lambda = 2 find the probability that X>0.5. Homework Equations The Poisson PDF: P(x,\lambda) = \frac{\lambda^k}{k!}e^{-\lambda} The Attempt at a Solution Usually with these sorts of probability problems where they ask...

Homework Statement I have a project for my statics class. My topic is equilibrium of a rigid body, and I am building an assembly that will have four different support reactions. They will all be attached to one central post for ease of construction, but they will be analyzed as separate...

"any superset of a support is also a support" Wikipedia: Let f:R-->R: f(x) = 1 if x is in (-1,1), otherwise let f(x) = 0. Then support1 of f, "the set of points where the function is not zero" is (-1,1), and support2 of f, "the closure of that set", is [-1,1]. In either case, there is a...

I'd like to hear what people have to say about the following paper, which is way beyond my level knowledge, but could be exciting(?): http://arxiv.org/abs/1104.2302

I didn't use the format because my question is more general. I want to be able to understand the logic so I can apply it where appropriate. We're finding forces (and whether they're in tension or compression) using the Method of Joints and Method of Sections. I don't understand why...

[b]1. There is a beam with labels point A on the left hand side of the beam and point B on the right hand side of the beam. The beam is supported by bolts on side B (that can handle up to 4000 lb). There is no support on side A, so a support has to placed at some distance from B to support the...

Are "rockers" and "rollers" mobile support? I'm reading about trusses and trying to understand this sentence: . I presume they mean mobile support that only has 1 resistance direction. Am I correct?

Physics Forums has opened an affiliate account with Amazon.com. 5-7% of any purchase you make is sent to Physics Forums. Think about buying your school textbooks and other materials this way. Just click this link and the tracking system will register that PF sent you. Easy! Thanks...

Homework Statement A long uniform board weighs 62.6 N (12.5 lbs) rests on a support at its mid point. Two children weighing 317.0 N (63.4 lbs) and 500.0 N (100.0 lbs) stand on the board so that the board is balanced. What is the upward force exerted on the board by the support? Homework...

Hello, given a function f:R->R, can anyone explain what is meant when we say that "f has compact support"? Some sources seem to suggest that it means that f is non-zero only on a closed subset of R. Other sources say that f vanishes at infinity. This definition seem to contradict the...

Unusual paper: http://arxiv.org/abs/1102.1108 Some planets get ejected from their systems and wander off into interstellar space. The authors investigate what would be needed for such a planet to remain able to support ocean-floor life for a protracted period on the order of a billion years.

IS it possible to design a sloping roof (as shown in fig)? if yes please help in placing of beams.] thanks

Are my reaction vectors correct? Truth be told I'm not exactly sure what am I looking it... but did I get it right?

Very basic question, I am almost embarrased to ask it... If I had to hold say a clock or a wall unit above the ground it would take energy for me to do so. I would need to eat food to get energy to support the clock in my arms, and if I ran out of energy I would drop it. If I put a nail in...

Card provided one half of an a4 size (105mm x294mm) The card is fashioned into a beam and will be subjected to a load test. Rules 1. The card may only be folded to form a beam; you can cut it to suit your needs. It must NOT be rolled into a tube. Not permitted to use Glue, Adhesive tape...

Homework Statement Pluto is believed to have a radius of 1500 km, a mass of 1.5x10^22 kg, and a surface temperature of 55 K. Could Pluto support an atmosphere of methane, CH4? Homework Equations The Attempt at a Solution First some information: The problem is from a book...

Homework Statement OMG, Embarrassing typo ^ *HEAT not HEART. :) Sorry! In any case, A construction worker uses a steel tape to measure the length of an aluminum support column. If the measured length is 18.6 m when the temperature is 21.2 C, what ist he length when the temperature rises to...

Hey ya'll. I've been struggling pretty hard with the course material at UC Irvine and am starting to question if this is the field for me or not. In an effort to find support (and help with homework), I've decided to get involved on this forum. So you'll be seeing me around. Please offer advice...

Homework Statement A hiker, who weighs 986 N, is strolling through the woods and crosses a small horizontal bridge. The bridge is uniform, weighs 3550 N, and rests on two concrete supports, one at each end. He stops one-fifth of the way along the bridge. What is the magnitude of the force...

So I have this graphics card and I don't understand why its specs say "no" for 1080p support. http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=5274435&CatId=3669 It says max resolution 2560x1600 and 1080p is only 1920x1080. I use a 32" LCD for my monitor and my...

I applied to three universities to enter a PhD program in string theory (I know, it's not much). All three rejected me. One of them rejected me purely for financial reasons. Since I am motivated, I bargained with it to start my PhD without financial support and got accepted. It's possible I...

A 49" dia. steel tube (shell) with a 6" x 57.5" dia. steel ring (Tire) welded to the tube rotates horizontally at ~ 27 RPM. Inside of the shell are 42 - 2.5"dia x 6' long solid steel rods. It is held at one end by a 5" dia. bearing mounted shaft, at the other end the Tire sits on 2 bearing...

Homework Statement The two angled ropes used to support the crate in the figure below an withstand a maximum tension of 1800 N before they break. What is the largest mass the ropes can support? picture of the crate and ropes...

This came up in the Guns thread so I guess I should just make a new thread. I can't stand by while people talk about things they have no idea about. Just spreading blatant misinformation in the form of 'I believes'. To be completely honest with you I don't care what you believe. Not to...

I need to replace an air conditioner compressor unit that sits on the 2nd floor walk way on my stilt home in the Florida Keys. The walk way is 24" deep and the original AC unit fit that dimension, however, the new unit is 31" square. When I install the new unit I would like to leave a 18" space...

Homework Statement A T-shaped bracket supports a 150-N load as shown. Determine the reactions at A and C when (a) \alpha=90o, (b) \alpha=45o ans: (a)A=150N going down, C=167.7N,63.4degrees (b)A= 194.5N going down; C=253N, 77.9degrees base on the book...

http://www.usatoday.com/news/washington/judicial/2010-06-21-supreme-court-anti-terror_N.htm Interestingly, this case was argued by the Solicitor General, Elena Kagan, who argued: http://www.usatoday.com/news/washington/judicial/2010-02-23-terrorism-law-appeal_N.htm?csp=obinsite The logic...

My wife and I support the World Wildlife Fund, the National Wildlife Federation, and the Arbor Day Foundation to try to preserve habitat, fund research and repopulation efforts, and encourage tree-growth. We have a life-time supply of return address labels and little note-pads, though I wish...

My questions are: - Will a proposed bracket be able to support 7500 lb. without undue or permanent distortion or failure? - Can the proposed dimensions be improved? The bracket will be attached to a large tree and will support one end of the 4x6 redwood swingset beam. (On the other end...

Hi, I have a question concerning the asymptotic boundary conditions on matter fields and the Riemann tensor. What is the precise relation between saying that "the matter fields go to zero at spatial infinity" and "the matter fields have compact support"? And how natural is it to state that...

f(x,y) = x + y is the joint probability density function for continuous random variables X and Y. The support of this function is {0 < x < 1, 0 < y < 1}, which means it takes positive values over this region and zero elsewhere. g(x) = x + (1/2) is the probability density function of X...