***Hint from professor: Please remember that in translation the summation of moments of forces is always equal to the moment of the m a_G vector, not zero. The m a_G vector originates at G and the sign of the moment of this vector only depends on whether the moment is clockwise or counterclockwise, never on whether a_G itself is positive or negative. The normal force in problem 1 is never zero and there is no need to use any angle for the force P because the horizontal and vertical components of this force may be determined directly using summations of forces and moments. Also remember that one may take moments about any point. In practice, one selects a moment point that eliminates the moments of as many unknown forces as possible.

***Hint from professor: Please remember that in translation the summation of moments of forces is always equal to the moment of the m a_G vector, not zero. The m a_G vector originates at G and the sign of the moment of this vector only depends on whether the moment is clockwise or counterclockwise, never on whether a_G itself is positive or negative. The normal force in problem 1 is never zero and there is no need to use any angle for the force P because the horizontal and vertical components of this force may be determined directly using summations of forces and moments. Also remember that one may take moments about any point. In practice, one selects a moment point that eliminates the moments of as many unknown forces as possible.