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MAE 241 - Statics
Summer 2009
Dr. Konstantinos A. SierrosOffice Hours: M and W 10:30 – 11:30 (263 ESB new add)
[email protected] Blog: http://wvumechanicsonline.blogspot.com
1) Members AC and AB support the 300-lb crate. Determine the tensile force developed in each member.
2) If θ = 45°, determine the moment produced by the 4-kN force about point A.
3. Serious neck injuries can occur when a football player is struck in the face guard of his helmet in the manner shown, giving rise to a guillotine mechanism. Determine the moment of the knee force P = 50 lb about point A.What would be the magnitude of the neck force F so that it gives the counterbalancing moment about A?
4.9 Reduction of a simple distributed loading
• In some cases a body may subjected to a loading that is distributed over its surface• This is called distributed loading• Consider the beam which is subjected to pressure loading that varies only along the x axis• This loading can be described with respect to x
p = p(x) in N/m2
4.9 Reduction of a simple distributed loading
• p = p(x) in N/m2 contains only one variablex and we can represent it as a coplanar distributedload • Therefore, we can multiply the loading functionwith the width b
i.e w(x) = p(x)b in N/m
• We can replace the coplanar force system with aSingle equivalent force FR
Magnitude of FR
Therefore, FR is equal to the total area A under the loading curve
Chapter 5: Equilibrium of a rigid body
Objectives• Develop equations of rigid body equilibrium• Free body diagram for rigid bodies• Solve rigid body equilibrium problems
5.1 Conditions for rigid body equilibrium
FR = ΣF = 0 (MR)o = ΣMo = 0
5.1 Conditions for rigid body equilibrium
Equilibrium in two dimensions
Each wing tire supportsthe same load T
5.2 Free body diagramsSupport reactions
1)
2)
3)