Question

Consider the system of two masses and two pulleys as shown in fig. The pulleys and string are weightless and all surface are frictionless. The tension in the string is: $(g=10m/s^2)$

• A. $0N$
• B. $5N$
• C. $10N$
• D. $20N$

Answer 1

The correct option is C $10N$

Given : $m=2kg$

Let the tension in the string be $T$ and acceleration of the blocks be $a$.

The forces acting on the block are shown in the figure.

For block B :

$ma=T$ .....(1)

For block A :

$ma=mg-T$

Using (1) we get, $T=mg-T$

$⟹$ $T=\frac{mg}{2}$

Thus $T=\frac{\left(2\right)\left(10\right)}{2}=10N$