A block A with mass 100 kg is resting on another block B of mass 200 kg. As shown in figure a horizon rope tied to a wall holds it. The coefficent of friction between A and B is 0.2 while coefficent of friction between B and the ground is 0.3. The minimum reqired force F to start moving B will be

Options

A. 900 N
B. 100 N
C. 1100 N
D. 1200 N

Answer

C

Explanation

`F=f_(AB)+f_(BG)=mu_(AB)m_Ag+mu_(BG)(m_A+m_B)g`
`=0.2 xx 100 xx 10 +0.3(300) xx 10=1100N`