$(7)$ If the wood used for the T$-$beam has an allowable tensile and compressive stress of $(S_{\text{a}\text{l}\text{l}\text{o}\text{w}}{)}_t=3$MPa and $(s_{\text{a}\text{l}\text{l}\text{o}\text{w}}{)}_c=5$MPa, respectively, determine the maximum allowable internal moment $M$ that can be applied to the beam.