Question

Two blocks $A$ and $B$ are arranged as shown in the figure. The mass of block $A$ is $10\text{kg}$. The coefficient of friction between block $A$ and the horizontal plane is $0.2$. The minimum mass of block $B$ to start motion will be

• A. $2\text{kg}$
• B. $0.2\text{kg}$
• C. $5\text{kg}$
• D. $10\text{kg}$

Answer 1

The correct option is A $2\text{kg}$

For equilibrium
FBD

$N=10g$
$T_{max}=mg$
$T_{max}=f$
$\Rightarrow f=mg$
$\Rightarrow \mu N=mg$
$10\mu =m=2\text{kg}$ this will be the minimum mass to make the system move or we can say the maximum mass to keep the system in equilibrium.