The maximum range of a gun on horizontal plane is $$16 \mathrm{~km}$$. If $$\mathrm{g}=10 \mathrm{~ms}^{-2}$$, then muzzle velocity of a shell is

The trajectory of projectile is

For a projectile motion, the angle between the velocity and acceleration is minimum and acute at

A particle starts from the origin at $$t=0$$ with a velocity of $$10 \hat{\mathbf{j}} \mathrm{ms}^{-1}$$ and move in the $$x$$-$$y$$ plane with a constant acceleration of $$(8 \hat{\mathbf{i}}+2 \hat{\mathbf{j}}) \mathrm{ms}^{-2}$$. At an instant when the $$x$$-coordinate of the particle is $$16 \mathrm{~m}, y$$-coordinate of the particle is