Question

It was calculated that a shell when fired from a gun with certain velocity and at an angle of elevation $\frac{5\pi }{36}$ radian should strike a given target. In actual practice, it was found that a hill just intervened the trajectory. The angle of elevation at which the gun should have been fired in order to hit the target is:

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

Answer 1

Answer: (D)

$\frac{13\pi }{36}$ radian

Two projections, fired with same velocities under identical circumstances, but with different angle of projections have same range if the angles of projections have sum $=\frac{\pi }{2}$
Required angle $=\frac{\pi }{2}-\frac{5\pi }{36}=\frac{13\pi }{36}$