No, the velocity of impact on the ground would not be the same for projectiles launched at different angles, even if they have the same initial speed and are launched from the same height. The reason for this is that the angle at which a projectile is launched affects both its horizontal and vertical components of velocity.
When a projectile is launched at an angle, its initial velocity can be divided into two components: the horizontal component and the vertical component. The horizontal component remains constant throughout the motion, while the vertical component changes due to the influence of gravity.
The time of flight and the range of a projectile depend on its initial velocity and launch angle. The time of flight is determined by the vertical component of velocity and is influenced by gravity. The range is determined by the horizontal component of velocity.
Therefore, when projectiles are launched at different angles, they will have different time of flight and ranges, and their velocities of impact on the ground will be different. The angle of launch affects the vertical motion of the projectile, which, in turn, affects the time it takes to reach the ground and its final vertical velocity at impact.