Question

Three blocks of masses $m_1$, $m_2$ and $m_3$ are connected by massless strings as shown in the figure and placed on a frictionless table. They are pulled with a force $T_3=40N$. The tension $T_2$ will be: (Given $m_1=10kg,m_2=6kg$ and $m_3=4kg$)

• A. $20N$
• B. $40N$
• C. $10N$
• D. $32N$

Answer 1

The correct option is D $32N$

Common acceleration for the system is given by
$a_{net}=\frac{F_{net}}{m_{total}}=\frac{40}{10+6+4}=2m/s^2$

From the FBD of $m_3$, we have

$40-T_2=m_3\times a_{net}$
$⟹40-T_2=4\times 2$
$⟹T_2=40-8$
$⟹T_2=32N$