10.帶狀制動器,拉力側之拉力F1較鬆弛側之拉力F2為大,兩拉力之差為有效挽力F,輪鼓之直徑為D,則制動扭矩為 (A)F1✕ D/2 (B)F2✕D/2 (C)(F1-F2)✕D/2(D)(F1+F2)✕D/2
請問為什麼答案是D?