47. 如【圖二】所示,球直徑d,台階高h =0.25d,球重100N,問水平力T多大時,才能將球拉動?
(A)T=57.7 N (B)T=173.2 N (C)T=86.6 N (D)T=141.4 N
47. 如【圖二】所示,球直徑d,台階高h =0.25d,球重100N,問水平力..-阿摩線上測驗