Question

Two masses $A$ and $B$ of $10Kg$ and $5Kg$ respectively are connected with a string passing over a friction less pulley fixed at the corner of a table as shown in figure. The coefficient of friction of $A$ with the table $0.2$.The minimum mass of $C$ that may be placed on $A$ to the prevent it from moving is equal to:

• A. $15Kg$
• B. $10Kg$
• C. $5Kg$
• D. Zero

Answer 1

The correct option is A $15Kg$

$5g=T⟶\left(i\right)$

$(10+m)\mu g=T⟶\left(ii\right)$

$(10+m)\left(0.2\right)g=5g$

$5=2+0.2m$

$m=15Kg$