Question

Two masses of 5kg and 3 kg are suspended with the help of massless inextensible strings as shown in figure. The whole system is going upwards with an acceleration of $2m{s}^{-2}$. The tensions $T_1$ and $T_2$ are respectively :(Take g=$10m{s}^{-2}$)

• A. 96 N, 36 N
• B. 36 N, 96N
• C. 96N, 96 N
• D. 36 N, 36 N

Answer 1

Answer: (A)

96 N, 36 N

The free body diagram of 3 kg block is as shown in the fig. (a).
The equation of motion of 3 kg block is $T_2-3g=3a$
$T_2=3(a+g)=3(2+10)=36N$ ............(i)
The free body diagram of 5 kg is as shown in the Fig.(b).
The equation of motion of 5kg block is
$T_1-T_2-5g=5a$
$T_1=5(a+g)+T_2$
$=5(2+10)+36=96N$ (Using (i))