Statics Definition and 906 Threads

  1. W

    What is the angle between coupled forces with a given moment and magnitude?

    Homework Statement The moment of the couple is 600k (N-m). What is the angle A? F = 100N located at (5,0)m and pointed in the positive x and positive y direction -F = 100N located at (0,4)m and pointed in the negative x and negative y direction Homework Equations M = rxF M = DThe Attempt at a...
  2. A

    3D Statics Equilibrium - Dot Everything with Vector P?

    Homework Statement Bead B has negligible weight and slides without friction on rigid fixed bar AC. An elastic cord BD has spring constant k = 3 N∕mm and 20 mm unstretched length, and bead B has a force of magnitude P in direction BC. If bead B is positioned halfway between points A and C...
  3. A

    Statics - Moment using both vector and scalar approaches

    Homework Statement Homework Equations Mo=Fd Mo=r x F The Attempt at a Solution Alright guys, I did the whole process but I'm pretty sure I just made a little bump somewhere in my calculations which screwed up my answers. First I found everything I could find OA = 350j, so the unit vector...
  4. K

    Unsolvable tension force problem

    This was a problem on an exam that our professor later discovered was unsolvable THE WAY HE POSED THE QUESTION. First off, it's important to note that this is from a statics class, therefore Fnet = 0 will be true for all problems in our course. So here's my thoughts on this and I would like to...
  5. thegreengineer

    Vector mechanics for engineers -- Confusion described below

    Homework Statement Look I have an exercise about trusses in vector mechanics. It's the following: https://scontent-lax3-1.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/12003339_1645511085733429_8210043018491702007_n.jpg?oh=4955534403fb6f3f5f9a40c9c0b8ecbc&oe=569761ED I have to determine the forces in...
  6. A

    Engineering statics equilibrium problem

    Homework Statement Here is the prompt/picture The hint given is a FBD of the bead is recommended to being this problem. Find the coordinates of B so that both the magnitude and orientation of the elastic cord force can be properly represented. Also, two mutually orthogonal normal force...
  7. A

    Maximum weight a bar and cables can hold before breaking

    Homework Statement A weight W is supported by bar AO and cables AB, AC, and AD. Point A lies in the xy plane, if the bar and cables have the strengths listed below, determine the largest value W may have. Hint given: A FBD of joint A is recommendedto being this problem. Bar AO should be...
  8. A

    Force needed to support Suspension of a Vehicle

    Homework Statement A model for the suspension of a vehicle is shown where the spring has stiffness k = 178 N/mm and an unstreched length of 347 mm. http://imgur.com/1dTVs12 Determine the value P and the force supported by member AB so that the suspension has the equilibrium position shown...
  9. W

    Setting up systems of forces and free body diagrams

    Homework Statement Suppose I've got a static mass on a downward plane. (For instance a car on a drive way). How would you set up this free body diagram? Homework Equations F = f1+f2...etc The Attempt at a Solution My preference is A, but I've seen it displayed in examples in my book as B...
  10. A

    Statics: four crates, four springs, free body diagram

    Homework Statement In figure (a), four identical crates weighing 2,000 lb each are stacked one on top of another, and in figure (b) a simple model for determining the deformation of the stack of crates is shown. In this model, each spring has the same stiffness k = 4,500 lb/in. and the forces...
  11. A

    Equilibrium of a Collar and Pulley System with Spring - Free Body Diagram

    Homework Statement A collar with a pulley slides on a frictionless vertical bar GH. A string A B C D is wrapped around, where portion AB of the string is horizontal. A spring with 2.5 lb/in. stiffness is placed between the collar and point H. The spring has 7 in. unstreched length and 5 in...
  12. erickbq

    [Statics - Torques] Determining Coefficient of Static Friction

    Homework Statement The top of a ladder of L and mass m is connected to a wall by a horizontal cable. The ladder makes an angle Θ=60 with the horizontal. A woman of mass 2m finds that as she climbs the ladder, the ladder begins to slip when she is one-third of the way up the ladder. Find the...
  13. M

    Tensile/Bearing stress in a cantilever member.

    Two steel straps are use to hold member BCD level. The size of each strap is 12 mm thick and 50 mm wide. A 16 mm diameter bolt is used to connect thesteel straps to the 89 x 89 mm post at A. A 25 kN is applied at the free end of the cantilever at point D. Determine: the tensile stress developed...
  14. erickbq

    [Statics - Torques] Determining the tension of a string

    Homework Statement A 10.0kg sphere is attached to the incline by a horizontal string. Determine the tension in the string. Homework Equations (F⃗ net)x=ΣFx=0 (F⃗ net)y=ΣFy=0 Στ=0 τ = (radial disance)(F) The Attempt at a Solution 1. I began by determining all the relevant forces associated...
  15. D

    What are the forces acting on point A in this statics problem?

    Homework Statement Homework Equations : d = sqrt of dx^2 + dy^2 + dz^2 The Attempt at a Solution :[/B] [/B] Q1: The second image is the solution diagram. What I don't understand is that why is the force acting from A towards B? Shouldn't it be from B towards A? I'm thinking of it as A as...
  16. A

    What is the force required to keep two blocks in equilibrium

    Homework Statement Blocks A and B each weight 170 lb and rest on frictionless surfaces. They are connected to one another by cable AB. Determine the force P required to hold the blocks in the equilibrium position shown and the reactions between the blocks and surfaces. Hint given: This...
  17. A

    Finding largest value of H of a ramp, from a FBD

    Homework Statement The dimension h is to be determined to that a worker can comfortably slides boxes weighing up to 106 lb up and down a frictionless incline. If the worker can apply a 50 lb horizontal force to the box, what is the largest value h should have? Hint given: Before taking any...
  18. O

    Solving 2D Force Systems for Calculating Equilibrium

    Homework Statement I attached a picture of the question. Homework Equations ∑Fx=0 ∑Fy=0 100kg(9.8)= 981 N I am not sure how to start this problem. Everything else in this chapter is a breeze so perhaps a small insight or how to start would be sufficient, thanks.
  19. M

    Calculating Moments: Forces on a Ratchet Wrench

    Homework Statement Two 20 lb forces are applied to a ratchet wrench down at A and up at B to loosen bolt β. Find the sum of the moments of the two forces about the axis (x) of the bolt. Homework Equations What are the moments at point A, B, and Q? How do I find the moment about the x-axis and...
  20. W

    What Does the Variable T Represent in Cable Tension Problems?

    Homework Statement The Tensions in four cables are equal: |T1| = |T2| = |T3| = |T4| = T Determine the value of T so that the four cables exert a totl force of 12,500-lb magnitude on the support. (Inser a picture of 4 connected cables angled 9, 29, 40, 51 degrees respectively) My question...
  21. R

    What causes the liquid to rise in this picture?

    This is a diagram of a pitot-static tube. My question is however not related to its applications but rather, what causes the liquid to rise up the static tube? The static tube is at right angles to the fluid flow. I understand that this is a very basic question but I can't seem to get my head...
  22. I

    Question on Statics -- San Francisco Bay Bridge Bolts

    Homework Statement http://cisephysics.homestead.com/files/NewSanFranciscoBridge.pdf My question is on this problem. For some reason, I have trouble seeing which direction the force is pushing when it comes to statics. In this case, why is the column pushing up? I thought it would be going down...
  23. Handsome jack

    How Can You Find Forces P, F, and T in a Static Equilibrium Problem?

    1. Homework Statement Find forces P,F,and THomework Equations Fx = 0 Fy = 0 The Attempt at a Solution So far I only got force T from getting the moment from point b. Don't know how-to start getting force P and F since they're both at the same point. Any help will be much obliged thank you [/B]
  24. H

    How to find forces in wires at equilibrium

    I need to find tensions in suspensions wires on the picture: I wrote 4 equilibrium equations for moments in A, B, C, D and equilibrium about y-axis, but i got matrix with rank two. \begin{pmatrix} 3 & 2 & 1 & 0 \\ 0 & 1 & 2 & 3 \\ -1 & 0 & 1 & 2 \\ -2 & -1 & 0 & 1 \\ 1 & 1 &...
  25. D

    Statics problem -- Hinged members and anchor points supporting a mass

    Homework Statement Member BC exerts on Member AC a force P directed along line knowing that P must have a 325 N horizontal component, determine (a) the magnitude of the force P, Homework Equations Trig I suppose The Attempt at a Solution So I'm not sure if this correct I found two angles...
  26. D

    Particles Statics: Tension in Ropes & Angle Alpha

    Homework Statement Two tugboats are pulling a barge. if the resultant of the forces exerted by the tugboats is a 5000-lb force directed along the axis of the barge, determine (a) the tension in each of the ropes, give then alpha = 45 (b) the value for alpha for which the tension in rope 2 is...
  27. O

    Easy statics problem -- Block being hoisted by a pulley and rope

    I drew a FBD about point A and came up with the two equations: ∑Fx=0 20sinθ - T-ab(cos70)=0 ΣFy =0 -20cosθ + T-ab(sin70) -20=0 My answer is not coming out so I either messed up on the FBD or the equations, some help would be appreciated. I'm on 3-10 by the way.
  28. S

    Statics: tension in cable holding gate closed

    1. Homework Statement The tension in the cable is 800LBs. Find the depth of water that produces this tension. The gate is hinged at B; the cable is attached at A. (Figure 1)Homework EquationsThe Attempt at a Solution OK, so this is just 2 opposing lever arms: the tension in the cable is...
  29. M

    Beam statics: continous load analysis

    Homework Statement I just don't understand how to set the problem for the free body diagram (point (a) and (b)). Can someone help me with this problem? Thank you in advance.
  30. S

    Statics - 3 forces acting at a point -- angle α maxima

    Homework Statement Please if anyone could help me with this question . Two wires AC and BC are attached to the top of pole CD . The force exerted by the pole at C is vertical and the 2.5 kN force applied at C is horizontal and makes an angle α with the direction of the x-axis . Find the...
  31. L

    Two hanging masses and three strings

    Homework Statement Two masses m and M (where M = 2m) are attached with strings. One mass m is suspended from a single verticle string held by two strings each at 45 degrees to the horizontal. The suspending string to the left at 45 degrees is attached to a fixed point. The string on the right...
  32. J-dizzal

    Statics, friction of a rope around a post

    Homework Statement A dockworker adjusts a spring line (rope) which keeps a ship from drifting alongside a wharf. If he exerts a pull of 190 N on the rope, which has 1.25 turns around the mooring bit, what force T can he support? The coefficient of friction between the rope and the cast-steel...
  33. S

    Statics problem -- Frame supported by pin connections....

    Problem is here, http://s24.postimg.org/3y6wpyncl/frame.png I'm looking at this problem with the top and bottom beams being separate members and doing a FBD of both separately. However I'm unsure about the points where we have tension/compression. Like at point B, do I include a y component...
  34. N

    Engineering statics: Truss Analysis Question

    Homework Statement So I was working on this problem, and my only questions are wether BE and CE can be assumed to be no force members? Also if I am not sure a member is a no force member, will it be revealed once I do the calculations, Homework Equations ΣF = 0 The Attempt at a Solution I...
  35. J-dizzal

    Statics, equilibrium sphere in a groove on an incline plane

    Homework Statement The smooth homogeneous sphere rests in the 132° groove and bears against the end plate, which is normal to the direction of the groove. Determine the angle θ, measured from the horizontal, for which the reaction on each side of the groove equals the force supported by the end...
  36. I

    Question on intrepretation of loading

    hello all, I am in the process of measuring coefficients of a rectangular panel using given table in textbooks to obtain them. I have attached a simple figure of two situations; left is my current situation to analyze- a clamped end and compressive force on the other end. The situations...
  37. Frederica Salt

    Understanding the Moment of a Force: Statics of Rigid Bodies

    How can I identify the direction of a force in finding its moment? :rolleyes:
  38. N

    What is the equation for calculating resultant force in Engineering Statics?

    Homework Statement Homework Equations F^2 (resultant ) = F1^2 + F2^2 -2F1F2cos(theta) The Attempt at a Solution i calculated the magnitude using the equation above and it ended up being : F (resultant) = F sqrt(2-2cos(theta)) i don't know how to solve for the angle.
  39. J-dizzal

    What is the Height at which the Resultant of Three Forces Acts?

    Homework Statement Determine the height h above the base B at which the resultant of the three forces acts. Homework Equations M=Fd The Attempt at a Solution not sure how to get the height here. thanks im assuming the distance they are asking is less than 72 in. but I am not sure how to...
  40. J

    Why Does Virtual Work Seem Incorrect in This Statics Problem?

    1. The problem statement, all variables and /known data Help! I'm stuck on an exceedingly simple statics problem, number 2.24 in the New Millennium edition of exercises for the Feynman lectures. The problem consists of an inclined plane (inclination angle 30 degrees) on wheels with a...
  41. jdawg

    Understanding Forces in 3D Space: Solving Problems and Formulas Explained

    I'm having trouble number 2.61. I have the answers, but I don't understand why they are doing what they're doing. They have this for (Fx)1:(Fx)1=(80 lb)*cos(30)*cos(40)=53 lb I'm familiar with the formula Fx=Fcosθ , but I'm confused about using it in 3D. Is there a formula that I need to...
  42. Prashant91

    Which Introductory Statics Textbook is Best for First-Year Engineering Students?

    Hi All I am currently doing a 1st year engineering course. The course is called applied mechanics and focusses on statics. Could someone recommend a good introductory statics textbook. The link below is the unit outline for my course...
  43. X

    What exactly is moment, and when is it zero?

    I've been dealing with the concept of moment this whole year, in statics/dynamics but I've never really completely understood it, just rather memorized it. What I think moment is: If some point on a body has moment, then this means it wants to rotate. So moment is essentially what causes...
  44. D

    (Vector statics) Effect of a pulley on free body diagram?

    For example, a 1-m bar fixed to a wall holding a weight of 100 N, like this: How will the free body diagram of the second case different from the first?
  45. D

    How do I know which direction the horizontal force acts

    Homework Statement I am to find the reactions of a 3 pin frame. Homework EquationsThe Attempt at a Solution So how do I know which direction to label the horizontal reactions? In the diagram HA and HF are in the same direction, I was under the impression that reactions are opposite to applied...
  46. B

    Statics problem: man lowering himself from tree w/ friction

    Homework Statement The 180-lb tree surgeon lowers himself with the rope over a horizontal limb of the tree. If the coefficient of friction between the rope and the limb is 0.60, compute the force (P) which the man must exert on the rope to let himself down slowly. Homework Equations T1/T2...
  47. S

    Statics Problem Tipping Refrigerator

    Homework Statement A refrigerator with a mass of 100kg measures 150cm high by 75 cm wide by 75 cm deep. How much force applied horizontally at the top edge of the front will make it start tipping backward? Assume that the center of mass is at the center of the refrigerator. Homework Equations...
  48. S

    Multiple distributed loads on a beam

    Hi all, my professor has hinted at proposing a question of this sort to us for a shear and bending moment diagram. Now while I am comfortable with having [either] a uniformly distributed load or a varying one, I'm not sure how to deal with both. I can't seem to find anything in my textbook to...
  49. I

    What are the Internal Forces at Point C in a Distributed Load System?

    Homework Statement find internal normal, shear, and moment forces at point C, P=8kn The Attempt at a Solution for the most part I can solve this entire question but looking at the solution for it one of my equations is different and I cannot figure out why. my equation for finding T(tension...
  50. S

    Statics: find torque at door hinges

    Homework Statement Door weighs 20kg, and is held open by force P at doorknob opposing 15kg weight attached at C and wrapped around pulley. Theta is 90 degrees, so door is on x axis. Find torques on hinges A & B[/B]Homework Equations P is 118.8N in -k direction, which agrees with answer in...
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