Question

Two masses of$1kg$ and $5kg$ are attached to the ends of a massless string passing over a pulley of negligible weight. The pulley itself is attached to a light spring balance as shown in figure. The masses start moving during this interval; the reading of spring balance will be :

• A. more than $6kg$
• B. less than $6kg$
• C. equal to $6kg$
• D. $noneoftheabove$

Answer 1

Answer: (B)

less than $6kg$

$\begin{array}{c}\text{Let us assume thate}\\ \text{acceleration of the}\\ \text{Blocks' be (a)}\end{array}$

$\text{FBD on}5Kg\text{Block}$

$\Rightarrow 50-T=5a-\left(1\right)$

$\text{F BD on 1 kg Block}$

$\Rightarrow T-10=a-\left(2\right)$

$\begin{array}{c}\text{Let us assume thate}\\ \text{acceleration of the}\\ \text{Blocks' be (a)}\end{array}$

$\text{FBD on}5Kg\text{Block}$

$\Rightarrow 50-T=5a-\left(1\right)$

$\text{F BD on 1 kg Block}$

$\Rightarrow T-10=a-\left(2\right)$

$\begin{array}{c}\\ \text{on solving eq}\left(1\right)\text{and}\left(2\right)\\ \text{we get}T=16.67N\Rightarrow 2T=33.34N=3.334kg\end{array}$

$\begin{array}{c}\\ \text{on solving eq}\left(1\right)\text{and}\left(2\right)\\ \text{we get}T=16.67N\Rightarrow 2T=33.34N=3.334kg\end{array}$