[20分]BASIC結構力學

(1)
Vertical component of P = Psin 30 kN
Moment induced by P at A = - Psin 30 x 2 = -100 sin 30 x 2 = -100 kNm
Moment at A due to the BM at C = +120 kNm
Net moment at A = -100 + 120 = 20 kNm

(2)
Moment induced by P at A = - Psin 30 x 2 kN
Moment at A due to the BM at C = +120 kNm
Summation of BM at A = 120 – Psin30 x 2.
If BM at A has to be zero, 120 – Psin30x2 = 0 kNm, P=120 kN