Telekinesis

Spell, PHB 82.

Changing direction

Changing direction is permissible, though deceleration will be at the same rate as acceleration (doubling or halving). Decelerating objects will come to a stop on the round the halving brings the velocity below 2“/rd. In cases where the caster attempts to turn an object moving at high speed, a movement class (A, B, C, whatever) will applied by the DM.1) TODO: Explicitly map speeds to movement classes.

Hovering

Keeping an object hovering in place (zero acceleration) is allowed.

Casting on the unwilling

Like teleport, a saving throw is permitted if the target is unwilling.