16. A particle moves on the curve \( y = x + \sqrt{x} \) so that the x-component has velocity \( x'(t) = \cos t \) for \( t \geq 0 \). At time \( t = 0 \), the particle is at the point \( (1, 0) \). At time \( t = \frac{\pi}{2} \), the particle is at the point
