Question

Two blocks are in contact on a frictionless table. One has mass $m$ and other 2 $m$ . A force $F$ is applied on 2 $m$ as shown in figure. Next the same force $F$ is applied from the right on $m$ . In the two cases respectively, the ratio of the force of contact between the two blocks will be

• A. 2 : 1
• B. 1 : 3
• C. 1 : 2
• D. 3 : 1

Answer 1

Answer: (C)

When force $F$ is applied on $2 \,m$ from left, contact force,
$F_{1}=\frac{m}{m + 2 m}F=\frac{F}{3}$
When force $F$ is applied on $m$ from right, contact force
$F_{2}=\frac{2 m}{m + 2 m}F=\frac{2 F}{3}$
$\therefore F_{1}:F_{2}=1:2$