Question

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

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

Answer 1

Answer: (B)

Spring balance reading is equal to $2T$
tension in the string $=\frac{2 m_{1} m_{2}}{m_{1} + m_{2}}=\frac{2 \times 5 \times 1}{6}=\frac{5}{3}$ $Kgf$
reading of spring balance= $2T=2\times \frac{5}{3}=\frac{10}{3}$ $Kgf$