A particle starts from rest. Its acceleration $$a$$ versus time $$t$$ is shown in the figure. The maximum speed of the particle will be

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