rake angle
A horizontal angle is an angle between lines on a horizontal plane.
Lines
If they are not parallel and do not intersect then they would not be in the same plane (not possible), but they would be called skew lines.
They can be, but not necessarily. If two lines in the same plane never intersect, they are parallel. Though, two lines can exist in the same plane without being parallel. Ie, two lines that intersect at a 90 degree angle are perpendicular. Most lines in a plane aren't parallel.
They are called skew lines.
It is because they are not in a plane that is parallel to the horizontal.
In plane geometry, a shape with four sides, two of which are parallel and have the same length, cannot have a reflex angle.
A horizontal angle is an angle between lines on a horizontal plane.
Increasing the angle between two bones is called extension. This movement typically occurs in the sagittal plane and usually straightens or lengthens the joint.
Lines
No, a plane mirror does not converge a parallel beam of light. It reflects light rays without changing their direction, so the reflected beam remains parallel to the incident beam.
They have the same angle relative to any plane or line and never intersect.
If they are not parallel and do not intersect then they would not be in the same plane (not possible), but they would be called skew lines.
They can be, but not necessarily. If two lines in the same plane never intersect, they are parallel. Though, two lines can exist in the same plane without being parallel. Ie, two lines that intersect at a 90 degree angle are perpendicular. Most lines in a plane aren't parallel.
Plane waves travel parallel to each other in the same plane hence the name.
No, the frictional force on a sliding body on a plane is always directed parallel to the surface of contact, opposite to the direction of motion. The angle between the frictional force and the normal force depends on the surface materials and conditions but is not always at the angle of friction to the normal.
They are called skew lines.