The points \(O\) and \(P\) are on a horizontal plane, a distance 8 m apart. A ball is thrown from \(O\) with speed \(u \mathrm{~ms}^{-1}\) at an angle \(\theta\) above the horizontal, where \(\tan \theta=\frac{4}{3}\). At the same instant, a model aircraft is launched with speed \(5 \mathrm{~ms}^{-1}\) parallel to the horizontal plane from a point 4 m vertically above \(P\). The model aircraft moves in the same vertical plane as the ball and in the same horizontal direction as the ball. The model aircraft moves horizontally with a constant speed of \(5 \mathrm{~m} \mathrm{~s}^{-1}\). After \(T \mathrm{~s}\), the ball and the model aircraft collide.
(a) Find the value of \(T\).
(b) Find the direction in which the ball is moving immediately before the collision.