Question

Two blocks of masses $3\text{kg}$ and $2\text{kg}$ are tied to two ends of an inextensible string which passes over a frictionless pulley. The tension in the string between ceiling and the axle of pulley is

• A. $24\text{N}$
• B. $36\text{N}$
• C. $48\text{N}$
• D. $64\text{N}$

Answer 1

The correct option is C $48\text{N}$

From the FBDs of blocks

$m_{1}g-T=m_{1}a...\left(i\right)$

$T-m_{2}g=m_{2}a...\left(ii\right)$

Solving these two equations for tension $T$

$T=\frac{2m_1{m}_2}{m_1+m_2}g=\frac{2\times 2\times 3\times 10}{2+3}=24\text{N}$

Now, $2T=2\times 24=48\text{N}$