Question

Two blocks $A$ and $B$, each of mass $10kg$, are sliding on an incline. They are connected by a string. The coefficients of kinetic friction between block A and incline is ${\mu }_1=0.5$ and that between block B and incline is ${\mu }_2=0.4$. The tension in string will be (take $g=10m/s^2)$

• A. Zero
• B. $2N$
• C. $8N$
• D. $4N$

Answer 1

The correct option is D $4N$

Free body diagram of A


$T+60-40=10a$
$T+20=10a$....$\left(1\right)$
Free body diagram of $B$




$60-T-32=10a$
$28-T=10a$ .......$\left(2\right)$
From $\left(1\right)$ and $\left(2\right)$
$28-T=T+20$
$2T=8$
$T=4N$