Answer to Question #292299 in Classical Mechanics for mistra

Question

Block A rests on top of block Bas shown in (Figure 1). The table is frictionless but there is friction (a horizontal force) between blocks A and B. Block B has mass 6.00 kg and block A has mass 2.00 kg. If the horizontal pull applied to block B equals 12.0 N, then block B has an acceleration of 1.80 m/s2

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Answer 1

If the force is applied to both blocks so they move as a rigid system, their acceleration would be

$$a=\dfrac F{m_A+m_B}=1.5\text{ m/s}.$$