A mass of 10 kg is suspended by a rope of length 4 m, from the ceiling. A force F is applied horizontally at the mid-point of the rope such that the…

A mass of $\displaystyle 10$ kg is suspended by a rope of length $\displaystyle 4$ m, from the ceiling. A force F is applied horizontally at the mid-point of the rope such that the top half of the rope makes an angle of $\displaystyle 45^{\circ}$ with the vertical. Then F equals : (Take $\displaystyle \mathrm{g}=10 \mathrm{~ms}^{-2}$ and the rope to be massless)