From Mechanics

Revision as of 09:19, 8 March 2011 (edit) Ian (Talk | contribs) ← Previous diff		Current revision (09:29, 8 March 2011) (edit) (undo) Ian (Talk | contribs)
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		+	The weight acts at the middle point of the beam that is distance 0.5 m from <math>A</math>.
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	Taking moments about the point <math>A</math>:		Taking moments about the point <math>A</math>:

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Current revision

The weight acts at the middle point of the beam that is distance 0.5 m from \displaystyle A.

Taking moments about the point \displaystyle A:

\displaystyle \begin{align} & 1 \textrm{.}5\times {{R}_{B}}=0 \textrm{.}5\times 20\times 9 \textrm{.}8 \\ & {{R}_{B}}=\frac{ 0\textrm{.}5\times 20\times 9 \textrm{.}8}{1 \textrm{.}5}=65 \textrm{.}3\text{ N} \\ \end{align}

Taking moments about the point \displaystyle B:

\displaystyle \begin{align} & 1 \textrm{.}5\times {{R}_{A}}=1\times 20\times 9 \textrm{.}8 \\ & {{R}_{A}}=\frac{1\times 20\times 9 \textrm{.}8}{1 \textrm{.}5}=130 \textrm{.}7\text{ N} \\ \end{align}

Or use

\displaystyle {{R}_{A}}+{{R}_{B}}=20\times 9\textrm{.}8\ \text{N}

and only one of the above moment equations.