A bob is hanging from the ceiling of a specially designed room where a flow of air is being blown against. The bob is makes a $53^{\circ}$ angle with respect of the ground as indicated in the figure. The mass of the sphere is $2\,kg$. Assume that the wire is ideal. The flow of air excerts a constant force whose modulus is $4\,N$. Given these conditions, find the modulus of the force in $N$ in the wire when the sphere passes through its lowest point.

The alternatives are as follows:

$\begin{array}{ll}

1.&26.9\,N\\

2.&29.6\,\frac{m}{s^2}\\

3.&27.5\,\frac{m}{s^2}\\

4.&23.3\,\frac{m}{s^2}\\

5.&21.2\,\frac{m}{s^2}\\

\end{array}$

I'm not sure exactly how should I account for the force of air going against the bob.

What I think should be used here is the conservation of mechanical energy:

$E_u=E_k$

$mgh=\frac{1}{2}mv^2$

When the ball passes through the lowest point will be:

$T-mg=\frac{mv^2}{R}$

$T=\frac{mv^2}{R}+mg$

From the first equation:

$mgh=\frac{1}{2}mv^2$

$2g(1-\sin 53^{\circ})=\frac{v^2}{R}$

Therefore the tension will be:

$T=mg+\frac{mv^2}{R}=mg+2mg(1-\sin 53^{\circ})$

Therefore:

$T=2\times 10 + 2 \times 10 (1-\frac{4}{5})= 20 +20(\frac{1}{5})=24\,N.$ But this is not within the alternatives, needless to say that this doesn't seem to be the right answer. Can someone help here please?. I'm still stuck here.