How do I analyze a body with a 14 kip force at a point?

In summary, the student attempted to solve for the unknowns associated with the homework equation by using the principles of dimensional analysis. However, because the 14 kip force only acts on member AB, he was left with six equations and six unknowns.
  • #1
fayan77
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Homework Statement


Screen Shot 2019-02-03 at 4.23.19 PM.png


Homework Equations


Using dimensional plane in the vertical y and horizontal x.
##\Sigma##Fx = 0
##\Sigma##Fy = 0
##\Sigma##Mz = 0

The Attempt at a Solution


I have detached the 2 members at B and analyze them both separately. The 14 kip force is throwing me off though. When I detach the body do I still include a Bx and By force at B, on top of the 14 kip force?
 

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  • #2
fayan77 said:

Homework Statement


View attachment 238247

Homework Equations


Using dimensional plane in the vertical y and horizontal x.
##\Sigma##Fx = 0
##\Sigma##Fy = 0
##\Sigma##Mz = 0

The Attempt at a Solution


I have detached the 2 members at B and analyze them both separately. The 14 kip force is throwing me off though. When I detach the body do I still include a Bx and By force at B, on top of the 14 kip force?
In separating them, yes, you must include equal and opposite sets of Bx, By. For the X force, you just have to include it with one of them. If you need to answer for the values of Bx and By, it matters which you include it in. Looks like it is to be considered as applied to AB. But which you include it in does not affect any other reaction forces.
 
  • #3
But then I'm still left with 3 equations 4 unknowns. member AB x positive to the right y positive up moment positive counter clockwise.
##\Sigma##Fx=0: Ax+14-Bx = 0
##\Sigma##Fy=0: Ay-By = 0
##\Sigma##MA=0: -14(12) + Bx(12) - By(9) = 0

same with other member
 
  • #4
fayan77 said:
same with other member
Yes, but how many unknowns do you have altogether?
 
  • #5
Ax
Ay
Bx
By
Dx
Dy
6 unknowns
 
  • #6
fayan77 said:
Ax
Ay
Bx
By
Dx
Dy
6 unknowns
And six equations altogether, right?
 
  • #7
the only ones I could combine are the ones at connection B. However, that 14 Kip force only act on member AB correct?
If so then from member BCD I use
##\Sigma##MD = 0: 10(5)-By(10)-Bx(12) = 0
50 = 10By+12Bx from member BCD
168 = 12Bx-9By from member AB
solving for Bx and By and solve for the rest
 
  • #8
fayan77 said:
the only ones I could combine are the ones at connection B. However, that 14 Kip force only act on member AB correct?
If so then from member BCD I use
##\Sigma##MD = 0: 10(5)-By(10)-Bx(12) = 0
50 = 10By+12Bx from member BCD
168 = 12Bx-9By from member AB
solving for Bx and By and solve for the rest
Looks right.
 
  • #9
Thank you
 

Related to How do I analyze a body with a 14 kip force at a point?

1. How do I calculate the magnitude of the 14 kip force?

The magnitude of a force is the amount of force applied, which is typically measured in units of pounds or newtons. In this case, 14 kip is equivalent to 14,000 pounds. Therefore, the magnitude of the force is 14,000 pounds.

2. What is the direction of the 14 kip force?

The direction of a force is typically described using a coordinate system such as Cartesian or polar coordinates. In this case, the direction of the 14 kip force can be determined by specifying the angle and direction from a reference point. For example, the force could be described as 14 kip at 30 degrees from the positive x-axis.

3. How do I convert the 14 kip force to other units?

To convert the 14 kip force to other units, you can use unit conversion factors. For example, 14 kip is equivalent to 62.28 kilonewtons (kN) or 62,280 newtons (N). It is important to use the correct conversion factor to ensure accurate results.

4. Can I analyze the body with only the 14 kip force at a point?

In order to fully analyze a body, it is recommended to have multiple forces acting on the body. However, in some cases, a single force at a point may be sufficient to analyze the body's behavior. This depends on the complexity of the body and the type of analysis being performed.

5. How do I determine the effects of the 14 kip force on the body?

The effects of a force on a body can be determined by using principles of statics and mechanics. This involves analyzing the forces and moments acting on the body and calculating the resulting displacement, stress, and strain. Software programs such as finite element analysis can also be used to simulate the effects of forces on a body.

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