A particle \(P\) is projected with speed \(25 \mathrm{~ms}^{-1}\) at an angle \(\theta\) above the horizontal from a point \(O\) on a horizontal plane and moves freely under gravity. After 2 s the speed of \(P\) is \(15 \mathrm{~ms}^{-1}\).
(a) Find the value of \(\sin \theta\).

(b) Find the range of the flight.