Assuming the bullet was initially fired from ground level, the bullet’s vertical component of velocity would decrease considerably, perhaps almost to zero, by the time it reached a height of 2.0 km. This is due to the downward acceleration of gravity and also air resistance. The horizontal component of its velocity would also decrease, due to air resistance.
Work Step by Step
A projectile thrown at an angle above the horizontal will have both air resistance (vertical and horizontal) and gravity (vertical) negatively impacting its velocity.