Question

Figure shows two blocks A and B connected to an ideal pulley string system. In this system when bodies are released then: (neglect friction and take $g=10\frac{m}{s^2})$

• A. Acceleration of block A is 1 $\frac{m}{s^2}$
• B. Acceleration of block A is 2 $\frac{m}{s^2}$
• C. Tension in string connected to block B is 40 N
• D. Tension in string connected to block B is 80 N

Answer 1

Answer: (B), (D)

Tension in string connected to block B is 80 N


By length contrained
$a_{P_1}=\frac{a_A+a_B}{2}$
$\Rightarrow a_{p_1}=\frac{0+a_{p_2}}{2}$
$\therefore a_{p_2}=2a_{p_1}$
Now $a_{p_2}=\frac{a_c+a_p}{2}$
$\therefore a_{p_2}=\frac{a_{10kg}+0}{2}$
$\Rightarrow a_{10kg}=2a_{p_2}$
$\Rightarrow a_{10kg}=4_{a{p}_1}=4a$
For 40 kg
40g - 4T = 40 a...........(i)
For 10 kg
T = 10 (4a)..........(ii)
From (i) and (ii)
$a=2\frac{m}{s^2}andT=80N$
So, correct answers are B and D