Question

Two blocks of masses 2 kg and 4 kg are hanging with the help of massless string passing over an ideal pulley inside an elevator. The elevator is moving upward with an acceleration g/2. The tension in the string connected between the blocks will be (Take g = $10m/s{}^2$ ).

• A. 40N
• B. 60N
• C. 80N
• D. 20 N

Answer 1

The correct option is A 40N

As the elevator is going upward with acceleration $\frac{9}{2}$ so $2\log$ block with focal $2\times \frac{9}{2}$ downward & $4\log$ block with focal $4\times \frac{9}{2}$ downward as a prudes force.

$\Rightarrow$ weight $+$ pruedo $-T=ma$

or $4g+2gT=4a$ ------ $\left(1\right)$

$\Rightarrow T-(2g+9)=2ai.e.f=ma$

or $T-3g=2a$ -------- $\left(2\right)$

$\left(1\right)\times 1$ $\left(2\right)\times 2$ we get $69-T-(2T-69)=+a+a$

or $6g-3T+6g=0$

$T=\frac{12g}{3}=4g=40N$