Question

In the figure a smooth pulley of negligible weight is suspended by a spring balance. Weights of $1\text{kg}$ and $5\text{kg}$ are attached to the opposite ends of a string passing over the pulley and move with acceleration because of gravity. During the motion, the spring balance reads a weight of

• A. $6\text{kg}$
• B. Less than $6\text{kg}$
• C. More than $6\text{kg}$
• D. May be more or less than $6\text{kg}$

Answer 1

The correct option is B Less than $6\text{kg}$

Reading of spring balance is
Reading $=\frac{Thrust}{g}=\frac{4m_1{m}_2}{m_1+m_2}=\frac{10}{3}\text{kg}$
$\Rightarrow$ Reading $=3.33\text{kg}(<6\text{kg})$
Hence, the correct answer is (b).