How Do You Calculate Reactions at Supports in Equilibrium Problems?

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SUMMARY

The discussion focuses on calculating reactions at supports A and E in equilibrium problems using free-body diagrams. The user successfully calculated Ax as -100 ft-lb but struggled to find Ay and E. The correct approach involves summing moments about points E and A to derive Ay and Ey, ensuring that the net vertical force equals zero. The book provides Ay as -225 lb and E as 625 lb, confirming the need for accurate moment calculations.

PREREQUISITES
  • Understanding of free-body diagrams in statics
  • Knowledge of equilibrium equations in mechanics
  • Familiarity with moment calculations (M = F * d)
  • Ability to apply the conditions for static equilibrium (ΣF = 0, ΣM = 0)
NEXT STEPS
  • Study the principles of static equilibrium in mechanics
  • Learn how to construct and analyze free-body diagrams
  • Practice calculating moments about different points in structures
  • Explore examples of reaction forces in various support types (roller and pinned supports)
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Students in engineering mechanics, structural engineers, and anyone learning about static equilibrium and reaction forces in structures.

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Homework Statement



Draw the free-body diagram of the structure by isolating it from its supports at A and E. Determine the reactions at A and E.

[PLAIN]http://img715.imageshack.us/img715/7161/physics.png

Homework Equations



M = (Fy)*x, or M = (Fx)*y
where "x" represents horizontal distance and "y" represents vertical distance. "M" is the moment.

The Attempt at a Solution



I found Ax.

When I convert the moment (curved, pink arrow) to a force, I find that the moment and force at A must be equal and opposite to the 200 ft-lb moment.

-200 ft-lb = (2 ft)*Ax

Ax = -100 ft-lb

I have no idea how to find Ay or E.
The book says Ay = -225 lb; E = 625 lb

Can anyone help me get started? I'm not sure how to go about finding those two values!
 
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60 views and no answers?

can someone help me with this?
 
Have some patience, please. :rolleyes: Well, the supports aren't showm very clearly; I had to work the problem backwards and it appears that the frame is roller supported at E and pinned at A. Your method for the calculation of Ax is not correct...Ax must balance the applied force. Sum moments about E to solve for Ay; sum moments about A to solve for Ey; check your work by ensuring that F_net_y =0
 

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