4.如下【圖10】所示為簡支樑受力情形,試求:
ΣMA = 0 ,
6Rb - 40*4 - 70*2 = 0
Rb = 50 Σ
Ry = 0 ,
Ra+Rb = 70+40
Ra = 60
彎矩以剪力圖的面積求得
Mc = 60 *2 =120kgf-m
Md =50 *2 = 100kgf-m