A.MB=-iθA B.MB=iθA C.MB=2iθA D.MB=0
A.MB=0 B.MA=3iθA C.QBA=0 D.QAB=-3iθA/l
A.QBA=-3iθA/l B.QBA=-6iθA/l C.QBA=-12iθA/l D.QBA=0