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参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Passage 3 Questions 11 to 15 are based on the following passage: Scientists in India have invented a new way to produce electricity. Their invention does not get its power from oil, coal or other fuel...
A.
Because bullocks have long been used by Indian people
B.
Because bullocks walk slowly and are easy to control.
C.
Because there are few non-working bullocks in India
D.
Because there is not enough oil in India.
【单选题】图示为一方桌的对称平面，水平拉力P和桌子重W都作用在对称平面内，桌腿A、B与地面之间的静滑动摩擦系数为f。若在对称平面内研究桌子所受的滑动摩擦力。以下四种情况下哪一种说法是正确的？（）【图片】
A.
当 P = fW 时，滑动摩擦力为 F Amax = F Bmax= fW /2
B.
当 P = fW 时，滑动摩擦力 F Amax < F Bmax> fW /2
C.
当 P < fW 时，滑动摩擦力 F A=F B=fW /2
D.
当 P > fW 时，滑动摩擦力 F A + F B= fW