Question

A system of pullies and block is arranged as shown in the figure. Find
the acceleration of the block of 5 kg.
​

Answer 1

Answer:

I think so it is 10 upwards

Explanation:

Answer 2

Acceleration is 7.57$\frac{m}{s^{2} }$

Explanation:

Let tension in the wire be T

Let accelerations of the 2kg 6kg and 5kg block be $a_{2}$, $a_{6}$ and $a_{5}$ respectively

• Tension is an internal force.So net work done by tension should be zero

2T$a_{2}$ + 2T$a_{6}$ - T$a_{5}$  = 0

2$a_{2}$ + 2$a_{6}$ = $a_{5}$

• From FBD of 2kg block

2T - 2g = 2$a_{2}$

• From FBD of 6kg block

2T - 6g = 6$a_{6}$

⇒$\frac{2T}{3}$ - 2g = 2$a_{6}$

• From FBD of 5kg block

5g - T = 5$a_{5}$

⇒$\frac{T}{5}$ -g = $a_{5}$

Substituting above relations

T = $\frac{45g}{37}$

Substituting T in FBD of 5kg block we get

                    $a_{5}$ = $\frac{28g}{37}$

                     $a_{5}$  = 7.57$\frac{m}{s^{2} }$