Question

Two blocks are connected by a string as shown in the diagram. The upper block is hung by another string. A force F applied on the upper string produces an acceleration of $2m/s^2$ in the upward direction in both the blocks. If $T$ and $T$ be the tensions in the two parts of the string, then

• A. $T=70.8N$ and $T^{\prime }=47.2N$
• B. $T=58.8N$ and $T^{\prime }=47.2N$
• C. $T=70.8N$ and $T^{\prime }-58.8N$
• D. $T=70.8N$ and $T^{\prime }=0$

Answer 1

Answer: (A)

FBD of mass 2 kg FBD of mass 4 kg



$T-T^{\prime }-20=4\dots$(i)

$T^{\prime }-40=8\dots$ (ii)

By solving (i) and (ii) $T^{\prime }=47.23N$ and

$T=70.8N$