Question

Two blocks of $7kg$ and $5kg$ are connected by a heavy rope of mass $4kg$ and an upward force of $200N$ is applied on the upper block as shown in figure. Ratio of tension at the top P and mid-point Q of the heavy rope is ($g=10m{s}^{-2}$)

• A. more than 2
• B. more than 3
• C. less than 1
• D. less than 2

Answer 1

The correct option is D less than 2

Acceleration of the system,

$\overrightarrow{a}=Netforce,=\frac{200-TotalWeight}{7+4+5}=\frac{200-160}{16}=2.5㎧$

FBD of 7kg mass body

$\therefore 200-70-T_p=7a\Rightarrow T_p=112.5N$

FBD of the position PQ

$T_P-T_Q-20=2a\therefore T_Q=87.5N\therefore \frac{T_P}{T_Q}=1.286<2$