Solve the below problem:
Q: A 1.2* 2.4 m sheet of plywood is temporarily held by nails at D and E and by two wooden braces nailed at A, B, and C. Wind is blowing on the hidden face of the plywood sheet, and it is assumed that its effect can be represented by a force Pk applied at the center of the sheet. Knowing that each brace becomes unsafe with respect to buckling when subjected to a 1.8-kN axial force, determine
(a) The maximum allowable value of the magnitude P of the wind force,
(b) The corresponding value of the z component of the reaction at E. Assume that the nails are loose and do not exert any couples.
