question_answer 56)

                  A fighter plane is flying horizontally, at an altitude of 1.5 km with speed 720 km/h. At what angle of sight (w.r.t. horizontal) when the target is seen, should the pilot drop the bomb in order to attack the target?

Answer:

                  \[\tan \,\theta =\frac{h}{R}\]                 But \[R=\,u\times \,\sqrt{\frac{2h}{g}}\]                                 \[\therefore \]\[\,\tan \,\theta \,=\,\frac{h}{u\times \,\sqrt{\frac{2h}{g}}}\]                 or \[\tan \theta =\,\frac{1}{u}\,\sqrt{\frac{gh}{2}}=\,\frac{1}{200}\,\times \,\sqrt{\frac{10\times \,1500}{2}}\]                 \[=0.4330\]                 \[\therefore \]\[\,\theta =\,{{\tan }^{-1}}\,(0.4330)\,={{23.4}^{o}}.\]