Statics Definition and 906 Threads

  1. C

    Trouble with a classic statics problem

    Homework Statement You are given three weights and 3 pulleys. Each mass hangs below a single pulley, and the pulleys are all connected by strings. The middle weight is 3 kg, the other two are each 2 kg. There are two unknown angles at the central pulley, with respect to the horizontal such that...
  2. D

    Crate on a cable statics question

    Homework Statement Please refer to the attachment.Homework Equations Sum of x and y forces = zero Sum of moments about any point = zeroThe Attempt at a Solution By looking at the portion of the string under the crate, there are 3 forces acting on it, namely the two tensions at the side and the...
  3. I

    Basic Statics problem with scalar components and force

    Homework Statement Determine the scalar components Ra and Rb of the force R along the nonrectangular axes a and Also determine the orthogonal projection Pa of R onto axis a. Homework Equations n/a The Attempt at a Solution I tried setup rectangular coordinate but that didn't work...
  4. R

    Solve 4 Unknowns: Statics Question

    [PLAIN]http://img38.imageshack.us/img38/6997/forces99.jpg I'm unsure how to go about solving this. There's 4 unknowns. Ax Ay Cx and Cy but isn't there only 2 equations (sum of forces in x and y direction are equal to 0) that can be created in this situation?
  5. T

    Statics and CM - Ladder Problem

    Homework Statement A uniform ladder length L stands upon the ground; the coefficient of friction there is μ . It leans safely against a smooth (friction-free) wall with the base of the ladder at an angle ! to the horizontal. Jim is the same weight mg as the ladder, and so is Jim's friend...
  6. L

    Learn How to Use Lagrangians for Statics: Building Compound Shapes and Examples

    Is it possible to do statics using lagrangians? (specifically building up a compound shape like a bridge from constrained point masses). Where could I see an example of this?
  7. W

    Statics Problem: Weight Hanging from a Rope

    Homework Statement Mass hanging from the pulley in 50kg, the mass on the rope is 1kg. Please see attachment for details. The answer will be in terms on L. Homework Equations The sum of the forces in the y-direction and x-direction are equal to 0. The Attempt at a Solution Adding...
  8. M

    Finding the Coefficient of Static Friction for a Concrete Block and Tongs

    Homework Statement A 500-N concrete block is to be lifted by the pair of tongs shown. Determine the smallest allowable value of the coefficient of static friction between the block and the tongs at F and G. See Diagram: [PLAIN]http://img192.imageshack.us/img192/1315/sprob826.jpg...
  9. S

    Statics Question regarding Joint type & Reactions

    When solving for reactions in a 2D diagram as seen below, how does each type of joint affect the summation of forces in the x & y components? My problem asks to find the summation of forces in the x & y components, and has a smooth pin connection in the left of the beam and roller on the right...
  10. S

    Statics - 3 Dimensional Equilibrium

    Moment about an axis - Statics - 3 Dimensional Equilibrium Homework Statement The member is supported by a pin at A and a cable BC. If the load at D is 300, determine the x, y, z components of reaction at these supports. i.e Find the reactions at A and the tension in the cable BC Homework...
  11. T

    Statics : Force on Equilibrium Problem

    Homework Statement Three (3) Identical Cylinders each weighing 80.2 were tied together by a wire and was placed on a smooth horizontal surface as shown determine minimum tension acting on the wire. hint: the answer 20 < Tension < 30 Figure below...
  12. O

    Understanding Method of Sections: Why is Fy=2T2 - 981? | WikiBooks

    Okay, so I am trying to understand the method of sections so I can finish my homework. I look at http://en.wikibooks.org/wiki/Statics/Method_of_Sections" and for the life of me, I can't understand why at the bottom of the page it says Fy=0=2T2 - 981 . Where does the factor of 2 come...
  13. M

    Statics Problem, tension in crane

    Homework Statement The horizontal member ABC of the rig shown below weighs 1000 lbs and is supported by a pin B and cable EADC. Since the cable passes over pulleys at A and D, the tension is the same along the entire length of the cable. If the rig lifts 3000 lbs at a distance 12 feet from...
  14. C

    How to Solve a Challenging Statics Question: Expert Tips and Tricks

    Hello, I just found out about this site! I was hoping someone may be able to help me solve this problem
  15. H

    Does the Bottom Hinge's Vertical Force on a Door Produce Torque?

    Homework Statement This is a part of a larger problem, but I'm unsure of one part. Picture a door with its center of mass in its geometric center. The door is hanging on two hinges, one at the top and one at the bottom. If the pivot point while measuring torques is considered to be the top...
  16. O

    How to Find Angles in Equilibrium Equations?

    I am studying statics and more precisely multi force members. I understand the process about solving how to find reactions and forces in x and y directions. However, I have a great tendency to confuse it when if comes to figuring out angles to write equilibrium equations. Any help for me to...
  17. H

    Learning moments in statics currently

    Skip to the bottom for the short version... We are learning moments in statics currently, and I have a problem that asks me to resolve the force given into x and y components, then, using "the principle of moments" aka Varignon's Theorem, find the moment with that same force applied at...
  18. T

    Solving Basic Statics Homework: 17.0 & 3.5 Positive/Negative?

    Homework Statement http://www.mypicx.com/uploadimg/1510974339_04192010_1.png Homework Equations The Attempt at a Solution i've got everything i just can't understand how you figure whether the 17.0 and 3.5 are negative or positive, can someone tell me how you figure this?
  19. T

    Engineering Statics Center of Gravity Problem

    Homework Statement For the machine element shown, locate the x coordinate of the center of gravity. The picture of 2 different problems are attached Homework Equations V = 1/3*a*b*h The Attempt at a Solution I can figure out the coordinates fine for everything except the triangles...
  20. G

    Fluid statics seems easy but can't figure it out .

    Homework Statement A cylindrical tank of internal diameter 1.5m and length 2.0m is mounted on a trailer. When the tank is filled with water the combined weight is 55 kN. Find the weight of tank plus trailer with the tank full of methyl alcohol (relative density 0.789). Homework Equations...
  21. W

    Solving Statics Problem: 6-kg Plank, Forces at A & B

    Homework Statement A man holds a 6-kg uniform plank. Determine forces at A and B. A is at 1 end of the board and B is 0.6 metres further down. total length is 1.4 m Homework Equations w=mg M=fd The Attempt at a Solution there will be a force down at A and up at B. i think A will...
  22. F

    Fluid Statics Center Of Pressure

    Hey guys I'm needing some help here its to find the center of pressure on a plane vertical. Sorry guys for the way I've set out all of this but its the only way i know how basically I'm just wondering how to calculate the experimental and theoretical center of pressure of this lab I'm...
  23. L

    Statics - Balancing moment and resultant force

    Homework Statement Replace the force system with a resultant and specify where its line of action intersects AB from point B. so I guess the imagine didn't work... http://yfrog.com/htstaticspicp I realize it is very small I apologize for that, if anything in the picture is unclear please let...
  24. F

    Find the Moment (Torque) of the resultant in 3-D (Statics)

    Hey guys... This problem is driving me bonkers. I really am not asking you to calculate anything but I only ask how to figure out how to get r to use τ = r x F . My professor did not even teach us anything about resultants and 3-d moments Homework Statement Homework Equations MO= τ = r...
  25. H

    Statics - mass attached to a string. Find forces acting to keep in equilibrium

    Hey guys, this is my first time posting and I really need your help. I'm stuck on this question: A light inextensible string of length 40cm has its upper end fixed at a point A, and carries a mass of 2kg at its lower end. A horizontal force applied to the mass keeps it in equilibrium, 20cm...
  26. O

    Fluid statics specific gravity question

    Homework Statement A block of wood with a specific gravity of .6 with a volume of 100 cm^3 is made to just float in H2O by hollowing out some of the wood and replacing it with a substance of specific gravity of 6.5. How many grams of wood were replaced. Homework Equations Not totally...
  27. C

    STATICS couples problem (I solved it but it doesnt make sense)

    Homework Statement Homework Equations M = r x F, where r is "a vector directed from the line of action of one of the forces to the line of action of any other force" The Attempt at a Solution Well, for the 250 lb couple the r = {3i - 4j - 2k{, F = 250 {3/5i - 4/5j} M = {-400i - 300j} (I...
  28. M

    Solving Equilibrium Problem: Find Forces in Ropes and Ball & Socket Joint

    A rod weighs 180 lb and has a 400 lb load located at point A is suspended in the air by two lines runningfrom point A to points C and D and a ball and socket joint at E. Find the forces for the tension in eachline (rope?, cable?) (A to C and A to D) and the forces at the ball and socket joint...
  29. 6

    Solving Statics Problem: Equilibrium of Forces

    I have having trouble solving this statics problem, I sum up the forces and have C*cos(30) - B*cos(phi) = 0 in the positive x direction and C*sin(30) + B*sin(phi) - D =0 in the positive y direction B = 275 lbs and D = 300lbs I need to solve for C and phi, I have tried substitution...
  30. G

    Statics, ladder leaning against wall finding friction mass etc. really simple q.

    This Is really simple I just can't remember what way Sin and Cosine go Homework Statement Here is the problem: 7 (b) A uniform ladder rests on rough horizontal ground and leans against a smooth vertical wall. The length of the ladder is 5 m and its weight is 80 N. The angle between...
  31. jegues

    Statics (smooth pin reaction + tension)

    Homework Statement See figure. Homework Equations \sum F_{x} = 0 \sum F_{y} = 0 \sum M = 0 The Attempt at a Solution See figure (written in my writing). Are the tensions A and B suppose to be the same? I imagine not because they are at different angles so they have...
  32. R

    What is the Largest Ratio R/r for Equilibrium in a Frictionless Spherical Bowl?

    Homework Statement Three identical spheres of radius r are at rest at the bottom of a spherical bowl of radius R. If a fourth sphere is placed on top, what is the largest ratio R/r for equilibrium if there is no friction? Homework Equations Obviously F_net=0 since the sphere are in...
  33. K

    Find Tension in Rope: 45deg, No Moments @A

    Homework Statement Find the tension of the rope. Theta is 45 degrees and A cannot support any moments. Homework Equations Drag=0.5*Cd*(U^2)*A*rho The Attempt at a Solution While everything is known, I am unsure of the setup. I initially thought: T*(cos(45deg))=Drag But it doesn't work if...
  34. jegues

    Equivalent force systems (statics)

    Homework Statement See figure Homework Equations \sum F_{x} = 0 \sum F_{y} = 0 The Attempt at a Solution I'm confused as to how to check which systems are equivalent. Do I just have to simply reduce all the systems to one force? I tried comparing systems (a) and (b)...
  35. F

    Question about fluid statics and dynamics

    This is not a homework assignment but a general question about something I found in my textbook. It pertains to fluid statics and dynamics and it says that: We can make the flow of a fluid visible by adding a tracer. This might be a dye injected into many points across a liquid stream or...
  36. N

    What is the direction of forces exerted on a plank by a wall in statics?

    Homework Statement http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys211/oldexams/exam3/sp08/fig15.gif The force exerted on the plank by the wall is upwards. (True/False) Homework Equations The Attempt at a Solution In statics, when using \sumFy =...
  37. N

    Kinematics - Statics - Free Body Diagram

    Homework Statement https://online-s.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys211/spring09/homework/11/two-beams/fig3a.gif Two identical uniform beams, each of mass "M" and length "L", are symmetrically set up against each other on a floor with which they have a...
  38. A

    Bad idea? Taking Statics and Dynamics simulatneously

    I'm considering this for summer at my local university (it doesn't have summer I or summer II options). Is it possible to do dynamics and statics all at once? Thanks!
  39. K

    Mechanics statics problem- help

    Mechanics statics problem-- help http://img686.imageshack.us/img686/8831/45170185.jpg I've tried to solve for the maximum weight using moment equation about point A, and it gives way too large value of W as compared to the answer 836lb, so I assume the slipping rather than tipping would...
  40. D

    How do I compute the moment in my statics assignment?

    Statics assignment a bit urgent So here is my assignment. i wish that someone could help me. now i know that this system is statically determinate and that i can compute the forces. my problem is that i cannot figure out how i can compute the moment. the Aim of the assignment is to find all...
  41. K

    Statics Problem - understanding the directions.

    Homework Statement Ok so basiclly I know how to do the problems, but I'm confused when to make the force negative and when to ignore the negative. forexample: http://yfrog.com/jastaticsprobp solving part a: Moment at A = -24*39 -(-14*39) = 2028 notice how i had to do -(-14*39) to...
  42. I

    Solving a Statics Question - Reaction Force Ay

    Hello, so I have a statics question which I am having trouble with. The question is : A boom is supported by a ball and socket joint at A and a guy wire at B.If the loads in the cables are each 8kN and they lie in a plane which is parallel to the x-z plane, what is the magnitude of the reaction...
  43. T

    3D Equilibrium Statics Problems

    I'm so stuck on this problem. I got it completely wrong on my test because I don't even know where to start. All i recall is that we mus use the vector approach? The problem states: For the figure shown, calculate the reactions at point O due to the tensions in the two cables BA and BC...
  44. D

    Statics question about deflection

    Hi, I just have a question about the situation present below: http://img25.imageshack.us/img25/1409/staticstransrot.jpg So basically the goal is to find the deflections of points A, B, and C but I'm having trouble with analyzing this. At point A, there is a roller so the force will...
  45. N

    Statics question: calculate forces and reactions in tow-truck problem

    Homework Statement "A lifting mechanism is mounted on the back of a truck as shown: Calculate the forces in each member and the reactions @ A & B for alpha=0 Homework Equations Sum of moments about A=0: 0=(5000N)(1m)+(-5000N)(-1.25m)+(By)(.5m) By=2500N The Attempt at a...
  46. U

    Solving Statics HW Problem: Piston Velocity & Acceleration

    Homework Statement Using the diagram shown below for a simple reciprocating engine, determine (a) the piston velocity (velocity at point D) and (b) the piston acceleration (acceleration at point D) as functions of the crankshaft angle, θ. The dimensions are as follows: LAB=1.875”, LBD=6.0”...
  47. A

    How Do I Set Up Statics Forces and Moments Problems?

    Homework Statement In the attachment Homework Equations Sum of the forces in the X, Y, and Z Sum of the Moments in the X, Y, and Z. The Attempt at a Solution I don't believe I need help solving the problem, I just need help setting it up. I can find the vector of CD, which...
  48. J

    Statics problem solving reactions

    Hi, can anyone show the correct method of how to solve a problem like this. Got the answers from my book but have no idea how they get them? Thanks James
  49. P

    How Do You Calculate the Charge on Two Suspended Spheres Using Coulomb's Law?

    Homework Statement Two small spheres of 15 g each are suspended from a common point by threads of length 35 cm. Each thread makes an angle with the vertical of 20 degrees. Each sphere carries the same charge. Find the magnitude of this charge. Homework Equations F=(kq1q2)/r^2The Attempt at a...
  50. J

    Statics and use of similar triangles

    Homework Statement How come all thetas are equivalent? Please take a look at this drawing http://tinypic.com/view.php?pic=2aahe3d&s=4 The Attempt at a Solution By similar triangles?
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