What is Free body diagram: Definition and 250 Discussions

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. O

    Free Body Diagram tension help

    Homework Statement Homework Equations I already got the right answer in the book. The only issue I have is drawing the free body diagram which it doesn't show. I'm not sure how to include the tension of the bottom-most string into the first diagram. The Attempt at a Solution Its meant to...
  2. U

    Free Body Diagram: Ax & Ay Direction Matters?

    hey, i just want a confirm if this is correct. imagine a built-in or a fixed bar in the side of a wall. when drawing a free body diagram for the point where the wall and the bar are fixed there should be forces in both x and y and a moment of force. if we label the x and y forces on the bar...
  3. O

    Free Body Diagram Help | Physics Homework Problem | Equilibrium Explanation

    Homework Statement Well the problem I have with physics is the free body diagrams. The book gives examples of those easy ones where a book slides across the table and such. This problem has me kind of confused on how to draw it. You guys can go to this link for the problem...
  4. W

    Free body diagram for a bag of coins suspended by an elastic band

    Homework Statement Draw a free body diagram showing all the forces on the elastic band, and a free body diagram showing all the forces on the bag of coins Homework Equations F=-kx F=mg The Attempt at a Solution I drew the forces on the elastic band as T = mg (m = mass of coins...
  5. J

    Is my Free Body Diagram and Approach Correct for Finding Vertical Force on Tank?

    Im working on the problem below and trying to figure out if I have the right approach. I am checing to see if my free body diagram is correct. Also if finding the vertical force exerted on the bottom of the tank is just the differenence of the bouyant force and wieght of the cylinder as showin...
  6. P

    50 88lbs Plasma TV mount on Stand - Free Body Diagram

    50" 88lbs Plasma TV mount on Stand - Free Body Diagram Hi, I am building a customized stand for my palsma tv. I already have the base, made of 2" square iron tubes. I am about to design the mount for the screws, but I was wondering what forces should I consider for this. The base is in...
  7. P

    How Do You Draw a Free Body Diagram for a Box and Truck in Motion?

    1. 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...
  8. L

    Solving for Net Force and Acceleration: Free Body Diagram Help

    1. Probem Suppose a couch with a mass of 75 kg was resting on a frictionless floor. Roy wants to move the couch to the other side of the room so he pushes it with a force of 30 N for 5.0 seconds. a) Make a free body diagram of the couch. b) Find the net force on the couch. c) Find the...
  9. F

    Free Body Diagram: True or False?

    Homework Statement A free-body diagram is: A picture of the object. (True/False) A diagram that contains all the forces that the object exerts on other objects. (True/False) A diagram that contains all the forces acting on the object. (True/False) Homework Equations The...
  10. S

    Water in the Bucket: Free Body Diagram? (Vertical Centripetal Force)

    Water in the Bucket: Free Body Diagram?? (Vertical Centripetal Force) Homework Statement If a bucket tied to a rope is revolving vertically in an counter clockwise direction, what would be the Free Body Diagram of "water" in the bucket at the top position? Homework Equations There...
  11. F

    Free Body Diagram for a Baseball Hit by a Bat

    I am having problems with a couple of homework questions. IF anyone can help out that would be great. Homework Statement Neglect air resistance in this problem. Mark all that apply when answering each question. Which forces should be included in the free body diagram for a baseball at...
  12. J

    Free body diagram, inclined plane, and finding V from x vs t graph

    Homework Statement Draw and label the free body diagram of a block on a plane inclined 30 degrees from the horizontal. There is friction and the block is stationary. The magnitues of the vectors must be correctly scaled and the directions correct. And then my other question is how to find...
  13. B

    Physics Free Body Diagram Question

    Question: Draw and label the free body diagram of a block on a plane inclined 30Efrom the horizontal. .There is friction and the block is stationary The magnitudes of the vectors must be correctly scaled and the directions correct. 3. The Attempt at a Solution Draw 30 degree angle...
  14. E

    Is This Free Body Diagram of a Pendulum Correct?

    Homework Statement I am asked to draw a free body diagram of a pendulum and a bob with it's maximum amplitude of 30 degrees. Below is my attempt, I just forgot to say that theta is equal to 30 degrees, other than that is it right?Homework Equations noneThe Attempt at a Solution attached as a...
  15. E

    Learn How to Create Accurate Free Body Diagrams | Step-by-Step Tutorial

    Homework Statement http://img384.imageshack.us/img384/2760/picture1uw7.png http://g.imageshack.us/img384/picture1uw7.png/1/ I'm trying to setup a free body diagram for this problem, and I'm not even sure where to start with the angles. That is basically my question, when do I use cos and...
  16. T

    Screwed joint - free body diagram

    Homework Statement I have a square beam with a screwed joint at each end. I am trying to determine deflection under a uniformly distributed load. Homework Equations - What is a simplified form for the screwed joint? Is it to be assumed fixed at both ends? The Attempt at a...
  17. B

    Kinetic friction free body diagram

    A Physics 1AL student uses a force P of magnitude 80 N and angle θ = 70 (with respect to the horizontal) to push a 5.0 kg block across the ceiling of her room. The coefficient of kinetic friction between the block and the ceiling is 0.40. a) Draw a free body diagram of the system. b) What...
  18. D

    Free body diagram (centripetal force)

    Homework Statement simple question really - how do you draw the free body diagram for a car going around a corner? Homework Equations n/a The Attempt at a Solution i know the net force, the centripetal force, points towards the middle. i have an engine force pointing tangentally...
  19. H

    How Does Rolling Affect the Free Body Diagram in Different Frames of Reference?

    lets say there is ball inside a bus that is accelerating. When the bus accelerates, the ball dosent slip or move, due to strong static friction. so in Earths frame of reference, the only forces are the mg and Normal force. in the bus's frame of reference, there is a fictious force pushing the...
  20. D

    Free body diagram of hanging pot

    Homework Statement A hanging potted plant is suspended by a cord from a hook in the ceiling. Draw a free body diagram for each of these: (a) the system consisting of plant, soil, and pot; (b) the cord; (c) the hook. Homework Equations None. The Attempt at a Solution I'm not sure...
  21. P

    Free Body Diagram of a Fish Swimming

    I have this project to do; it's of a free body diagram of a swimming fish. But I can't seem to find any good sites that give much info about a fish swimming. All the sites come up as a fish out of water, or a person swimming. Does anyone know sites that may help, or the forces that act on the...
  22. D

    Free Body Diagram Homework: Forces to Consider

    Homework Statement When drawing a freebody diagram for just an elevator, not the people in it, what are all the forces that we have to consider? I just used Fg down and Ft up, but because it is accelerating up, I made Ft greater.
  23. manjuvenamma

    Why is free body diagram named as such?

    Let us consider a lift which is moving with a constant acceleration with a man inside. Now we know that the man exerts a force which is different from his weight depending on the direction of the movement. Now, when we consider the free body diagram of the lift do we take into consideration...
  24. M

    Solve Free Body Diagrams: Tension, Gravitational, Equations

    Homework Statement http://img258.imageshack.us/img258/7172/testiiifo2.jpg Here is an image of the problem (taken from a practice test.) Homework Equations F=ma The Attempt at a Solution I drew the free body diagrams for each, but I have no idea what the equation would be. I...
  25. E

    Help with free body diagram for circular motion

    Suppose you have an object (lets call it block A) resting on the edge of a circular rotating disk and sitting static on the disk. I'd like to visualize a free body diagram for this showing forces. These are the forces I believe are acting on it: - Fg - Force due to gravity - Fn - Normal...
  26. J

    Why Isn't the Child's Pulling Force Shown in the Free Body Diagram?

    I have a question for the question http://tinyurl.com/2mftmr The following is the solution for the question, and you can see the free body diagram for child only, chair only and chair and child as one system http://tinyurl.com/32ozt9 For the free body diagram of chair and child as one system...
  27. S

    Drawing a Free Body Diagram for Drainpipe in Forklift

    1. Hmm, I need to draw a Free Body Diagram for the picture posted below. 2. No relevant equations. Just a geometric diagram. 3. I've done what I think it could be using help from Wikipedia. Could someone tell me if its right? Am I missing any other forces? The original object...
  28. C

    Free Body Diagram Examples and Tips for a Simple Assignment | Homework Help

    Homework Statement Hey guys. My Physics teacher gave us an assignment to make a Free Body Diagram poster. He didn't give us any specifics, just told us that we can do whatever we want. I'm a little confused as to what I should do and how to make one of these. Could you give me an example of...
  29. O

    Free Body Diagram and Newton's 2nd

    Homework Statement http://img527.imageshack.us/img527/2125/diagramkl0.png The Attempt at a Solution My attempt is in the picture. I am trying to get the diagram done before I continue on because if I mess up in the diagram, my work is guaranteed to be wrong. So basically what I am asking is...
  30. B

    Designing a Curved Highway Exit Ramp

    Hi everyone, I just need some help on setting up a free body diagram with the appropriate forces acting on it. The question is: An engineer must design a curved exit ramp for a highway in such a way that a car, exiting at the posted speed limit of 17.88 m/s (40 mi/hr), does not depend on...
  31. R

    Free Body Diagram and tension force

    Homework Statement It is supporting a weight of 500kg g= 9.81 Homework Equations The Attempt at a Solution Is the tension force a moment? im just not sure what i should do with it at that angle to get my FBD Any help would be tops! thanks a heap
  32. C

    What Forces Act on a Piano in a Free Body Diagram?

    Identify the forces acting on the object of interest. From the list below, select the forces that act on the piano. 1. acceleration of the piano 2. gravitational force acting on the piano (piano's weight) 3. speed of the piano 4. gravitational force acting on Chadwick...
  33. Simfish

    Free body diagram of a person sitting on a wheeled chair

    So I am a person sitting on a chair that has wheels. Now, the question is - can I push the chair when I am sitting on the chair and have nothing to push against? [other than the chair]? Note that I have no contact whatsoever with the floor. From experience, I know I can. So why? Whenever i...
  34. L

    Free Body Diagram Q&A: Atmospheric Pressure?

    Hi! Was wondering if anyone could enlighten me as to whether the atmospheric pressure is to be considered when drawing the free body diagram of a book resting on a table? In addition to the normal force and the weight, does atmospheric pressure need to be included?
  35. S

    Free body diagram for each vehicle

    Homework Statement In the movie "Jurassic Park 2", a jeep is struggling to pull a trailer back up from over a cliff. The jeep is connected to the trailer by a cable. The jeep in on level ground and the trailer hangs from the cable over the of the cliff. The jeep has a mass of 850 kg and pulls...
  36. A

    Free body diagram : Compression and Tension

    P, Q, R, S are light rods attached to the wall with a force W acting at that point in the figure. Please explain whether Compression or Tension is acting on them respectively by using Free body diagram and proper explanation. Can I resolve W in this way so that we have a force in the...
  37. C

    Solve Free Body Diagram: 2 Boxes, m1=35kg, m2=45kg

    Homework Statement Two boxes of masses m=35kg and m2=45kg, are hung vertically from opposite ends of a rope passing over a rigid horizontal metal rod. They system starts moving from rest. Assuming that friction between the rod and the rope is negligible, determine the magnitude of (a) the...
  38. L

    Including force in free body diagram

    Question The number of forces acting on a car parked on a hill(with parking brakes engaged) is Answers 1,2,3,4 When i drew the free body diagram, i got 4 but I am not sure if i should include a force
  39. U

    Drawing a free body diagram on the mass

    Hi, I need some help with a question involving forces. I will appreciate greatly if someone can please have a look at this. Thanks. Question: A 2.00 kg mass, which is attached to a string of radius r, travels in a vertical circle. When the string makes an angle of \theta=52^o with the...
  40. J

    Learn How to Draw Free Body Diagrams for Various Physics Problems"

    how would u draw the free body diagrams for the following problems: 1. after a ball ball is hit: while it is in flight after leaving bat 2. pulling a fish out of the water accelerating it upward while it is in ari not water 3. as my car acelerates to the left, a pendant on a string...
  41. M

    Help Drawing Free Body Diagram

    I am trying to solve this problem but I am having a hard time drawing a free body diagram. Can someone please help me draw one so I can solve the problem http://img141.imageshack.us/img141/1662/untitled1pc1.jpg
  42. P

    Free body diagram friction homework

    while moving in, a new homeowner is pushing a box across the floor at a constant velocity. the coefficient of kinetic friction between the box and the floor is 0.41. the pushing force is directed downward at an angle beta below the horizontal. when beta is greater than a certain value, it is...
  43. W

    What Forces Are Needed to Balance a Weldment on a Wall?

    Hello all, Can anyone provide the magnitude of the forces required to maintain a balanced condition within my attached free body diagram? I need to build a weldment and attach it to a wall. The weldment has a horizontal component that will carry a 750 pound vertical load placed 13 1/2"...
  44. P

    Master the Art of Free Body Diagrams: Understanding Vectors and Scalars

    When we do free body diagram, we usually consider the vector as scalar. I think this is a very important point, but why my teacher didn't clarify a lot?
  45. P

    Free body diagram Homework Problem

    Can someone please help with this problem. I'm lost! 1. A 150 kg bear walks out onto a beam as illustrated in Fig P8.20 trying to get to a picnic basket with mass 10kg. The beam is 6m long and has mass 40kg (you can consider its weight to be concentrated at a point 3m from the wall. (a)...
  46. J

    What is the Free Body Diagram for a Chain with Four Links?

    hello. I need help drawing free body diagram for four links on a chain. The picture looks like this: | <-thats a rope 8 <-these are links; they should all be connected 8 heres a good picture of a chain: http://homepage.mac.com/kpreid/povray/chain.png the first link is connected...
  47. P

    Simple Free Body Diagram question

    I have a question in my textbook that I can't answer for the life of me. "A 6500-kg helicopter accelerates upward at .6 m/s^2 while lifting a 1200-kg car. (a) what is the lift force exerted by the air on the rotors?" Now, my diagram has a vector pointing up with a force of (6500*9.8)N...
  48. F

    Free body diagram for the block showing all the forces

    A block is held in place on a frictionless incline by a massless string. The string is horizontal. I have to sketch a free body diagram for the block showing all the forces exerted on the block.
  49. C

    Dynamics Problem HELP - Free body diagram

    IM in Phys.20 Got this question for an assignment. Tried it and got stuck. I really need help -------- When golfing, uphill and downhill putts present different levels of difficulty. Suppose a green has a 5.0 degree slope and the force of friction will be 0.10N...
  50. M

    Is my Free Body Diagram right?

    Howdy, I had Physics two years ago in High School and am now in Engineering Physics. I am trying to have a head start on everything and it is also a project, can anyone check my FDB for correctness? Thanks, Matt http://homepage.mac.com/jjacques2/fbd.gif
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