Free body diagram Definition and 257 Threads

A free body diagram consists of a diagrammatic representation of a single body or a subsystem of bodies isolated from its surroundings showing all the forces acting on it.
In physics and engineering, a free body diagram (force diagram, or FBD) is a graphical illustration used to visualize the applied forces, moments, and resulting reactions on a body in a given condition. They depict a body or connected bodies with all the applied forces and moments, and reactions, which act on the body(ies). The body may consist of multiple internal members (such as a truss), or be a compact body (such as a beam). A series of free bodies and other diagrams may be necessary to solve complex problems.

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  1. K

    Free body diagram of a beam construction

    Homework Statement Beams AC and BD are light (no mass) and they're conjoined at B. Points A and D are fixed but frictionless. The radius of the wheel is R and the weight hanging on the pulley has the mass m. Homework Equations Fx=0 Fy=0 M=0 The Attempt at a Solution I'm stuck at the very...
  2. nate crosby

    Free Body Diagram -- forces on a structure over a balcony wall

    Hi, I am trying to work out the forces involved at the contact points in a design of a structure over a balcony wall. I have drawn up the cross section of the situation equilibrium, with a tolerance. I want to find out what forces will be acting on the structure and the balcony wall when a...
  3. S

    What causes drag on a stationary car?

    See attached photographs. For the car problem, I think the drag should be smaller than the forward acceleration but I'm not sure. For the Rocket question, I am pretty sure I am correct but I'm not sure why. The drag and the weight would both be in the down position.
  4. T

    Free Body Diagram of Car on Mountain

    If a car is on top of a mountain moving with an initial velocity, will it only forces acting on it be the normal force counteracted by the force due to gravity?
  5. U

    How Do You Balance Forces in a Bicycle Free Body Diagram?

    Homework Statement Bicycle with a rider applying weight to on pedal. Draw as free bodies in equilibrium. There are different situations. Homework Equations N/A The Attempt at a Solution So I am working on part a). 1. I believe it is only referring to just the pedal, chain, and the two...
  6. kiwimia

    Help on a free body diagram and equation

    1. Relevant information This is a two-block-system on top of each other to the right side of a wall, both attached with springs that are also attached to the wall. A force is applied on the bottom block to the right direction, frictions occurred on both bottoms of the two blocks. Here is the...
  7. S

    Free body diagram of an incline

    Homework Statement For the maximum angle for which you have data draw a free body diagram and explain how the forces add to give the resultant (net) force and show the calculations required to determine the acceleration. The lab was about using Galileo's inclined plane to measure acceleration...
  8. N

    Free body diagram and applying Newtons law

    hello! this is a question that iv been working on and can't seem to figure it out, i checked out the other two threads on this same question but they were of no help, anyway here it is: A wedge with mass M rests on a frictionless horizontal table top. A block with mass m is placed on the wedge...
  9. G

    How do I model the motor in this free body diagram problem?

    Hi I have a problem in understanding the attached free body diagram problem. I have a shaft that is pivoted at the top. Below the pivot is a magnetic bearing with a radial stiffness of 2600N/mm. I've modeled this as a springs in parallel. Below the bearing is a motor with a radial stiffness of...
  10. G

    Free Body Diagram Forces of a Rope Hoisting a Weight via Pillars

    So I am designing an apparatus to lift a 500g load up 500mm and I am trying to find reactions. I have filled in these values in my head with my own logic but I don't know how to do the maths and if I am right or not. I can do the initial position ok but it is the final position I am unsure of...
  11. C

    Free Body Diagram of a Truck with a Box

    Homework Statement A large box containing your new computer sits on the bed of your pickup truck. You are stopped at a red light. The light turns green and you stomp on the gas and the truck accelerates. To your horror, the box starts to slide toward the back of the truck. (Assume that the...
  12. P

    Help With Drawing a Free Body Diagram

    Homework Statement A large box containing your new computer sits on the bed of your pickup truck. You are stopped at a red light. The light turns green and you stomp on the gas and the truck accelerates. To your horror, the box starts to slide toward the back of the truck. (Assume that the...
  13. L

    MHB Free Body Diagram Solve Problem: Find Force Normal

    SOLVE THIS PROBLEM And this is the figure I need the free body diagram because the book solve this problem in this way the force normsl is n = fcosx the verticall componente is fsenx = w + miuN why does the fr is vertical in this case?
  14. Greg Bernhardt

    What Are the Rules for Drawing a Free Body Diagram?

    Definition/Summary A free-body diagram is a diagram of all the contact and non-contact forces acting directly on a body (in a non-inertial frame, that includes "fictitious" forces). Indirect forces (such as the weight of a different body), and internal forces, should not be shown...
  15. L

    Physics Fundamentals : Free Body Diagram

    Homework Statement A 5.0kg mass is suspended from the ceiling. A horizontal force F is applied to hold the string in position as shown http://i.imgur.com/ZdR72ff.jpg Determine the reading of F on the spring balance by using a scale diagram Homework Equations None The Attempt at...
  16. J

    A couple questions regarding force and free body diagram

    Hey guy, I would like to ask a few question about force and free body diagram. First question, I conduct a compressive experiment a few day back, using compression machine to test the strength of different materials e.g., Aluminium, PVC and Ceramic. However there is one thing that I don't...
  17. E

    Understanding Friction in Car and Trailer: Free Body Diagram Help

    Homework Statement http://postimg.org/image/vnn9m9au9/ For the car why is the friction acting towards the left. Shouldn't it be towards the right since the car is moving to the left And why is there no friction for the trailer? Homework Equations The Attempt at a Solution
  18. P

    Free Body Diagram: Explaining 3 Cord Tensions for Block C

    Homework Statement http://postimg.org/image/5h0hvdi4l/ Can someone explain why the FBD of Block C would involve three cord tensions? Homework Equations The Attempt at a Solution
  19. samjohnny

    Free body diagram and force vectors

    Homework Statement Attached, where AC=BC=2R and CD=CE=3R. I need to work out the force the cylinder exerts on the cross section (in order to work out the moment at C). So first I'm trying to work out the free body diagrams for this system. Is it as I've attached? How do I draw the tension...
  20. T

    What Forces Are Acting on a Man Climbing an Incline?

    Homework Statement Draw a free body diagram of the incline. Build the free body diagram of the man. Which is the force which makes the man to go up the incline? http://imagizer.imageshack.us/v2/800x600q90/46/t92m.png Homework Equations Newton's 2º Law The Attempt at a Solution...
  21. C

    Can anyone help me check my free body diagram for mobile crane

    Homework Statement https://www.icloud.com/photostream/#AE5oqs3qHTNWQ;B21C49F3-02FB-4EA3-8CE5-D1E2C1FA7C49 Homework Equations The Attempt at a Solution https://www.icloud.com/photostream/#AE5oqs3qHTNWQ;A55D9431-FD6D-4884-9AFC-C4D7C8E39AF1
  22. marellasunny

    Free body diagram from whole system-direction of forces in free-body d

    Homework Statement A car and a trailer are connected by a joint. The car and trailer system are on a inclined place at a gradient of 8 degrees. The rolling friction coefficient along with other vehicle parameters are given.We are asked to draw the free body diagrams of the car and trailer...
  23. Jadaav

    Free body diagram - Weight and normal reaction

    Let's consider a stationary ball lying on the floor. The weight of the ball acts downwards and the normal reaction acts upwards. They are of the same magnitude but not of the same type. So normal reaction is the reaction to what, if not weight ?
  24. N

    Free body diagram of person in elevator Help

    Homework Statement A man is on an elevator - Draw a FBD of the man if the elevator accelerates upwards - Draw an FBD of the man if ele. accelerates downwards Homework Equations F=m*a w=mg The Attempt at a Solution My FBD For the first one "elevator accelelartes upwards" means...
  25. C

    What are the forces acting on the chandelier?

    Homework Statement See picture. Homework Equations The Attempt at a Solution I want to know what are all the forces acting on this object. If the object is 10N , the tension force suppose to be 10N. But wouldn' there be a normal force acting between the point touching the...
  26. F

    Finite Element analysis: Free body diagram help

    Homework Statement Hey guys, my problem is not really the end solution, but the preliminary step that I'm not too sure about. Given the following diagram: The image on the left is the given model, and the right image is my nodal element FBD, but somehow i don't believe that's correct. Can...
  27. N

    Draw a free body diagram of each object in centripetal acceleration

    Homework Statement Draw a free body diagram of each object in Italics, that is in centripetal acceleration, and name the force causing this centripetal acceleration. a. Moon in circular orbit around Earth. b. Electron in circular orbit around nucleus of atom . c. Snowboarder slides over...
  28. A

    Dynamics, Newton's laws, Problem with free body diagram and work

    Homework Statement A boy skateboards down a curved playground ramp. If we treat the boy and his skateboard as a particle of total mass m = 25:0 kg, he moves through a quarter-circle with radius R = 3:0 m. He starts from rest at point A and there is no friction. (a) Find his speed at the...
  29. R

    Free Body Diagram to find Force

    The attached image shows a diagram of the problem. I am trying to calculate the Compressive force in the piston (B). Would the methods shown work for finding the Comp Force? Thanks
  30. N

    How Do You Analyze Forces in a Non-Slipping Book Stack Scenario?

    A hand supports two books, ma and mb, with ma on top. The hand accelerates the books p and to the right, with a pushing force directed 64° above horizontal. Assuming the upper book does not slip, draw a free body diagram for each book. My attempt:
  31. S

    Pulley Hoist Free Body Diagram

    Hi All, I am an old dog, and rusty propeller head. I am having the most difficult time figuring out the forces on a pulley system I am working on. Can someone please review my sketch and tell me if I am even close. I would accept any suggestions and direction. Much Obliged -Steve
  32. F

    Maximum angular velocity and free body diagram

    Homework Statement I have found the question I am having trouble with here: http://www.chegg.com/homework-help/questions-and-answers/block-mass-m-rest-surface-incline-adistance-h-10cm-base-height-incline-ish-50cm--coefficie-q218123 Homework Equations See below The Attempt at a Solution After...
  33. G

    What is the Acceleration of a Couch Being Pushed at an Angle with Friction?

    Homework Statement An 82 kg couch is being pushed with a force of 56 N at an angle of 40 above horizontal. If the coefficient of friction between the couch and the floor is 0.051, what is the acceleration of the couch? Homework Equations The Attempt at a Solution
  34. J

    How to interpret a Free Body Diagram for a Kite in Flight?

    The wind is blowing with a force of 48 N against a kite that Taylor is flying, so that the tail of the kite makes an angle of 24° to the ground. I am just really confused on this, I attacted the solution would anyone mind explaining it? I have no idea on how to get this
  35. P

    Understanding Free Body Diagrams for Cantilevered Structures

    For the attached picture I need to draw a free body diagram for the structure supporting the pulley. At the fixed end (left), there would be a vertical and horizontal reaction force as well as a moment. I am not sure what the forces and moments would be for the part connected to the...
  36. T

    Free Body Diagram and applied force

    Homework Statement A cavewoman is dragging her 65.4 kg mate home, up a gentle 10° incline. The co efficient of friction for skin on oil is 0.40. What is the minimum applied force she needs to keep the neanderthal moving with uniform motion? Homework Equations ff=μFn fg=mg fnet=ma The...
  37. V

    Wrote general equation for a free body diagram

    So I derived this equation for the net force/acceleration of a motorcycle on a flat surface. I believe this equation could practically be used for any rolling object. ƩF = Fp - μ*Fn - FD Where: FP is the force of the bike acting against the ground, tangent to the ground FD =...
  38. M

    Free body diagram on moment and torsion

    Homework Statement It's not exactly a homework question, just want to see if i have the right concept in drawing free body diagrams See attached Picture. In case 1, the object is fastened on plane x-z and the rectangular block is fastened to the T-block in y-z plane. Will the force be...
  39. V

    Is the Free Body Diagram for C-Spanner Screw Failure Analysis Correct?

    Hi guys, I'm working on one assignment about C-Spanner screw an impeller failure analysis. However, we're unsure if the free body diagram we draw is correct or not, given that our calculated safety factor is unreasonable. Can anyone give us a hand and have a look. Moreover, if someone can...
  40. 1

    Free body diagram of man in a box

    Homework Statement A 60 kg man stands in a 30 kg box on a light weighing machine. If the box is kept at rest due to force applied by the man by the rope , what is the weight shown by the weighing machine? Homework Equations The Attempt at a Solution .answer given in book is 15...
  41. K

    How Do Forces Interact in Stacked 45 Degree Wedges with Friction?

    Homework Statement How would the free-body diagram of two 45 degree right angle wedges stacked on one another look like? (It is stacked so that the two wedges form a square) There is friction that is holding the wedges together. The wedges are in place and not moving. ___ |\ | | \| ----...
  42. 1

    Accelerating Car Free Body Diagram

    Homework Statement Identify all forces acting on the object and draw the free-body diagram. Draw the force vectors with their tails at the dot. The orientation of your vectors will be graded. The exact length of your vectors will not be graded but the relative length of one to the other...
  43. M

    Forces acting on a two object system using free body diagram

    Homework Statement A force of magnitude F= 7.30 N pushes three boxes with masses m1= 1.80kg, m2= 3.00kg and m3= 4.20kg, on a level surface. Draw a free body diagram showing all the individual forces acting on the system consisting of boxes 2 and 3 together. Indicate the directions of the...
  44. M

    Pulley Free Body Diagram Problem

    In the figure below, m1 = 10.5 kg and m2 = 3.5 kg. The coefficient of static friction between m1 and the horizontal surface is 0.50, and the coefficient of kinetic friction is 0.30. I've drawn the free body diagram myself and labeled it but don't know how to structure the equations and stuff...
  45. K

    Free body diagram of a truncated cone?

    Hi, I have a question about basic statics. I have heard from someone that the forces acting on a truncated cone in a hole of corresponding geometry is different from an ordinary block sliding down a wedge, since the normal force on one side of the cone will be affected by the normal force on...
  46. K

    Free Body Diagram for simply supported beam

    Homework Statement As shown in the attachment, a free body diagram (FBD) must be drawn Homework Equations sum of horizontal force = 0 sum of vertical force = 0 The Attempt at a Solution 1. Forces F1 and F2 appear exactly as they are in the FBD 2. At point A, there is an outward horizontal...
  47. X

    Statics free body diagram concept question

    Homework Statement See attachments Homework Equations The Attempt at a Solution In the explanation attachment, I don't get the last paragraph "Note that force Fce acts downward on bar...compression." Since from the figure Fce is pointing down, and Fbd is pointing up, shouldn't...
  48. U

    Free Body Diagram Help: Homework Equations and Attempts

    Homework Statement I feel that I am a bit fuzzy whether things are reaction forces. In the diagram I see there is a beam holding point B, and there are 3 forces: Cable BC, 500N, and 780N. My professor wrote: Ask yourself: is the beam holding the point from moving up or down, right or left...
  49. S

    Newtons third law, elevator question (free body diagram)

    Homework Statement An elevator containing 3 passengers(with a mass of 72kg 84 kg and 35 kg) has a mass combined of 1030 kg . The cable attached to the elevator exherts an upward force of 12000 N. But the friction opposing the motion of the elevator is 1400 N. a) Draw a free body diagram...
  50. B

    Free Body Diagram Help: Learn How to Draw It

    Homework Statement can anyone show me what the free body diagram of this would look like? Thankyou
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