1.若彈簧DB 未拉之長度為2m,欲維持40kg木箱於圖示位置,試求此彈簧剛性。

5.如圖三所示(Figure3) Determineθand the tension in the spring, which correspond to the equilibrium position of the spring. The unstretched length of spring is h and the constant of the spring is k. The pin and roller supporters are at A and C, respectively. The point load P works on B with the downward direction and neglect the weight of all objects. (20%)