Question

Block $A$ of mass $35Kg$ is resting on a friction less floor. Another block $B$ of mass $7Kg$ is resting on it as shown in the figure.The coefficient of friction between he block is $0.5$ while kinetic friction is $0.4$. If a force of $100N$ is applied to block $B$ , the acceleration of the block $A$ will be (g=$10m{s}^{-2}$

• A. $0.8m{s}^{-2}$
• B. $2.4m{s}^{-2}$
• C. $0.4m{s}^{-2}$
• D. $4.4m{s}^{-2}$

Answer 1

The correct option is A $0.8m{s}^{-2}$

Since two blocks moves separately the forces acting on $A={\mu }_{k}mg$
$=7\times 0.4\times 10=28N$
$\therefore$a=$\frac{F}{M}=\frac{28}{35}=0.8m{s}^{-2}$