No, in projectile motion, the velocity vector does not change as time passes if the object is moving in a straight line with constant acceleration.
In projectile motion, an object moves in a curved trajectory under the influence of both horizontal and vertical components of velocity. The vertical component is affected by the acceleration due to gravity, while the horizontal component remains constant (assuming no external forces are acting horizontally).
While the object is in motion, the magnitude of the velocity vector remains constant unless acted upon by external forces. However, the direction of the velocity vector changes continuously due to the influence of gravity on the vertical component. This results in a parabolic trajectory.
So, in summary, the magnitude of the velocity vector remains constant, but the direction of the velocity vector changes continuously in projectile motion.