- #1
Feodalherren
- 604
- 6
Homework Statement
Homework Equations
The Attempt at a Solution
I don't even know...
What are the forces involved in lifting a 1450-lb load with a hydraulic crane?
Click For Summary
Discussion Overview
The discussion revolves around the forces involved in lifting a 1450-lb load using a hydraulic crane. Participants are attempting to determine the forces in the hydraulic cylinder and the links of the crane mechanism while applying principles of statics.
Discussion Character
- Homework-related
- Mathematical reasoning
- Technical explanation
Main Points Raised
- Some participants express uncertainty about how to approach the problem, indicating a lack of clarity in their understanding of the forces involved.
- One participant suggests working back from the load and drawing separate free body diagrams for the crane components, applying equations of statics to find the forces in links AC and AD and in the hydraulic cylinder AB.
- Another participant discusses the forces at joints C and D, questioning whether to denote them as Cx, Cy, Dx, and Dy or to use different notations. They present equations for equilibrium but express confusion over their calculations.
- Participants share specific calculations for forces, including values for Fwc, WD, CD, and CA, but indicate that their results are incorrect, leading to further adjustments in their approach.
- One participant suggests taking moments about point D as a potential method to solve the problem.
Areas of Agreement / Disagreement
Participants do not appear to reach a consensus on the correct approach to solving the problem, as there are multiple expressions of confusion and differing methods proposed for analyzing the forces involved.
Contextual Notes
Participants mention specific angles and forces but indicate that some calculations are incorrect, suggesting potential issues with assumptions or interpretations of the geometry involved.
I don't even know...
- #2
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
- 12,828
- 1,673
Feodalherren said:Homework Statement
The hydraulic crane is used to lift the 1450-lb load. Determine the force in the hydraulic cylinder AB and the force in links AC and AD when the load is held in the position shown.
Homework Equations
The Attempt at a Solution
I don't even know...
Work back from the load and draw separate free body diagrams for the individual pieces comprising the crane mechanism. By applying the equations of statics to each piece, you should be able to establish te forces in links AC and AD and in the hyd. cyl. AB.
- #3
Feodalherren
- 604
- 6
So at joints C and D do I let there be a Cx, Cy and Dx, Dy respectively or do I just keep it as Fwd and Fwc? Either way I can't seem to solve it.
∑Fx=0=WD-4293cos19.74
ΣFy=0=Fwc Sin19.74 - 1450
Fwc= 4203 lb
WD = 4041 lb
Then at joint C∑Fx=0=CDsin30 - CAsin30 - 4041
∑Fy=0=1450-CDcos30-CAcos30
CD = 4878
CA = -3204
Incorrect.
Ah my angle was incorrect, substituted 19.74 with 6.18. Still incorrect.
∑Fx=0=WD-4293cos19.74
ΣFy=0=Fwc Sin19.74 - 1450
Fwc= 4203 lb
WD = 4041 lb
Then at joint C∑Fx=0=CDsin30 - CAsin30 - 4041
∑Fy=0=1450-CDcos30-CAcos30
CD = 4878
CA = -3204
Incorrect.
Ah my angle was incorrect, substituted 19.74 with 6.18. Still incorrect.
Last edited:
- #4
Dr.D
- 2,411
- 723
Take moments about D.
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