試題詳解

5.Block A, with mass ma, is initially at rest on a horizontal floor. Block B, with mass mb, is initially at rest on the horizontal top surface of A. The coefficient of static friction between the two blocks is Hh- Block A is pulled with a horizontal force It begins to slide out from under B if the force is greater than:
(A)mAg
(B) mBg
(C) u smig
(D)usmBg
(E)us(mA+mB)g