Halliday, Resnick & Walker — Motion in Two and Three Dimensions: Problem 41

Upon spotting an insect on a twig overhanging water, an archer fish squirts water drops at the insect to knock it into the water (Fig. 4.18). Although the insect is located along a straight-line path at angle \(\phi\) and distance \(d\), a drop must be launched at a different angle \(\theta_0\) if its parabolic path is to intersect the insect. If \(\phi = 36.0^\circ\) and \(d = 0.900 \text{ m}\), what launch angle \(\theta_0\) is required for the drop to be at the top of its parabolic path when it reaches the insect?