2. A 70 kg person stands on one end of a one-meter long board. The board is uniform and weighs 100 kg. How far is the center of mass of the system “person on board” from the person?(A) 0.1 m (B) 0.3 m (C) 0.5 m (D) 0.8 m (E) 0.9 m

19. 有一員工考績資料表，表單名稱為「員工考績」包含有下列兩個屬性：「姓名」、「考績」，其中考績分為五個等第，”優”>”甲”>”乙”>”丙”>”丁”，如要列出考績”丙”以下(含”丙”)的所有員工姓名，應該使用下列哪一個 SQL敘述？ (A)Choose 姓名 from 員工考績 where 考績 < ”乙” (B)Select 姓名 from 員工考績 where 考績=”丙” OR 考績=”丁” (C)Select 姓名 from 員工考績 when 考績 < ”乙” (D)Choose 姓名 from 員工考績 when 考績=”丙” OR 考績=”丁”

2. A 70 kg person stands on one end of a one-meter long board. The board is uniform and weighs 100 kg. How far is the center of mass of the system “person on board” from the person?
(A) 0.1 m
(B) 0.3 m
(C) 0.5 m
(D) 0.8 m
(E) 0.9 m

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