Question

It was calculated that a shell when fired from a gun with a certain velocity and at an angle of elevation $\frac{5\pi }{36}rad$ should strike a given target in the same horizontal plane. In actual practice, it was found that a hill just prevented the trajectory. At what angle of elevation should the gun be fired to hit the target.

• A. $\frac{5\pi }{36}rad$
• B. $\frac{11\pi }{36}rad$
• C. $\frac{7\pi }{36}rad$
• D. $\frac{13\pi }{36}rad$

Answer 1

The correct option is D $\frac{13\pi }{36}rad$

For same target there is two angle of elevator.

If one is $\frac{5\pi }{36}$ and if this route is present by hill then other angle is

$=\frac{\pi }{2}-\theta =\frac{\pi }{2}-\frac{5\pi }{36}=\frac{18\pi -5\pi }{36}=\frac{13\pi }{36}$