問題詳情
13. A boy pulls a wooden box along a rough horizontal floor at constant speed by means of a force
as shown. In the diagramf is the magnitude of the force of friction, N is the magnitude of the normal force, and Fg is the magnitude of the force ofgravity. Which of the following must be true? 
(A) P = f and N = Fg
(B) P = f and N ＞ Fg
(C) P ＞ f and N ＜ Fg
(D) P ＞ f and N = Fg
(E) None of the above.
參考答案
無參考答案
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