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LiviaPimentel
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Homework Statement
The uniform beam shown in the IMAGE below has a weight W. If it is originally resting while supported on A and B by cables, determine the pull on cable A if cable B suddenly fails. Admit that the beam is a slender rod.
IMAGE:
Homework Equations
TotalTorque=I*α →TotalTorque= T*L/4=I*α ; α=a/(L/4) ; in which a=acceleration of the rod
W - T = m*a
W-T = m*T*L^2/(16*I)
The Attempt at a Solution
Well, in my attempting of solving the problem, I considered that the moment of inertia utilized
in these equations is equal to m*(L^(2)/3). This is the moment of inertia of a bar that rotates around a point of its end. What I can not understand is why the teacher who provided the solution of this problem on the internet considered that I = m*(L^(2)/12), that is the moment of inertia of a bar that rotates around its center.
Can someone tell me why my way of thinking is wrong? (is it wrong?)
Thanks!