Find magnitude of tension in the string. $(g=10m/s^2)$   (in SI units).

F.B.D. of 10 kg block:
 
$T = 10 G = 100 N$
 F.B.D. OF PULLEY :
 
Since string is mass less, so tension in both sides of string is same. Force exerted by string
 $=\sqrt{{\left(100\right)}^2+{\left(100\right)}^2}=100\sqrt{2}N$
Note : Since pulley is in equilibrium position, so net forces on it is zero. Hence force exerted by hinge on it is $100\sqrt{2}N$