Question

The maximum range of a gun on horizontal surface is $16km$. If $g=10$ $m{s}^2$, the muzzle velocity of the shell must be :

• A. $1600$ $m{s}^{-1}$
• B. $400$ $m{s}^{-1}$
• C. $200\sqrt{2}$ $m{s}^{-1}$
• D. $160\sqrt{10}$ $m{s}^{-1}$

Answer 1

The correct option is B $400$ $m{s}^{-1}$

For maximum range $\theta =\pi /4$
$R=\frac{u^2}{g}$

$u=\sqrt{Rg}=\sqrt{16\times {10}^3\times 10}=400m/s$