Figure P4 shows a rigid frame fixed at point A. A single force of magnitude
3000\, ext{N} 3000 N is applied at point B, acting along the direction shown (defined by the 3–4–5 triangle). The horizontal member has a length of 10 m , and the vertical member has a height of 12 m . Determine the reaction moment ( M A ) at the fixed support A. Use the sign convention for forces and moments shown in the figure (i.e. a counter clockwise moment is considered positive ). Select the correct answer (All answers are in N·m)
Figure P4. Cantilever beam with applied forces

Question

Figure P4  shows a rigid frame fixed at point A. A single force of magnitude  
 3000\,	ext{N} 3000 N  is applied at point B, acting along the direction shown (defined by the 3–4–5 triangle).  The horizontal member has a length of  10  m , and the vertical member has a height of  12 m . Determine the  reaction moment  ( M A ) at the fixed support A. Use the sign convention for forces and moments shown in the figure (i.e.  a counter clockwise moment is considered positive ). Select the correct answer (All answers are in N·m)   
 Figure P4. Cantilever beam with applied forces

Answer

M_A = - (3000)(10) = - 30{,}000\,	ext{Nm}

Answer

M_A = \frac{3}{5}(3000)(12) + \frac{4}{5}(3000)(10) = 45{,}600\,	ext{Nm}

Answer

M_A = \frac{4}{5}(3000)(12) - \frac{3}{5}(3000)(10) = 10{,}800\,	ext{Nm}

Answer

M_A = - \frac{3}{5}(3000)(12) - \frac{4}{5}(3000)(10) = - 45{,}600\,	ext{Nm}

Answer

M_A = \frac{4}{5}(3000)(12) + \frac{3}{5}(3000)(10) = 46{,}800\,	ext{Nm}

Answer

M_A = - \frac{4}{5}(3000)(12) + \frac{3}{5}(3000)(10) = - 10{,}800\,	ext{Nm}

Answer

M_A = \frac{4}{5}(3000)(10) - \frac{3}{5}(3000)(12) = 2{,}400\,	ext{Nm}

Answer

M_A = (3000)(10) = 30{,}000\,	ext{Nm}

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Figure P4 shows a rigid frame fixed at point A. A single force of magnitude ...

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