A mass M is hung with a light inextensible string as shown in the...

As there is a load at P , so tension in AP and PB will be different. Let these be $\mathrm{T}_1$ and $\mathrm{T}_2$ respectively. For vertical equilibrium of P , $\mathrm{T}_2 \cos 60^{\circ}=\mathrm{Mg}$ i.e., $\quad \mathrm{T}_2=2 \mathrm{Mg}$ ...(i) And for horizontal equilibrium of P , $\mathrm{T}_1=\mathrm{T}_2 \sin 60^{\circ}=\mathrm{T}_2(\sqrt{3} / 2)$ ...(i) Substituting the value of $\mathrm{T}_2$ from Eq. (i), $\mathrm{T}_1=(2 \mathrm{Mg}) \times(\sqrt{3} / 2)=\sqrt{3} \mathrm{Mg}$