(i) Before AB is cut.

(ii) Just after AB is cut.

i) Before AB is cut :

By Lami’s theorem

$∴\dfrac {T_AB}{\sin⁡(160)} = \dfrac { T_AC}{\sin⁡(140)} = \dfrac { 50}{\sin⁡(60) } \\ ∴T_AB=50 (\dfrac {\sin⁡(160)}{\sin⁡(60) })=19.75N \\ ∴T_AC=50 (\dfrac {\sin⁡(140)}{\sin⁡(60) })=37.11N$

ii) Just after AB is cut :

Applying static conditions of equilibrium,

$∴T_AC \sin70-50=0 \\ ∴T_AC=\dfrac {50}{\sin70 }=53.21 N …