Abody is placed on a rough inclined plane. why does the frictional force decrease with the increase of angle of inclination?

Why does the frictional force decrease with the increase of angle of inclination? The frictional force is calculated by the normal force * the coefficient of friction. The normal force is mg*cos(angle). When the angle is 0, the normal force is mg. However, as the angle increases, cos(angle) decreases and so mg*cos(angle) decreases. So the normal force decreases as the angle of inclination increases. It follows that the frictional force decreases since the frictional force is the normal force * the coefficient of friction.

The objects do not reach terminal velocity         there is not enough time from the time the object falls from when it hits the ground to achieve terminal velocity. an object must be placed higher to achieve terminal velocity in order to be in free fall.