Is it permissible for an elderly teacher to hit or pinch his adult female students to compel them to study, do homework, or avoid mistakes?

It is not permissible for a teacher to touch, pinch, or hit adult, non-mahram women with his hand, due to the prohibition of touching anything other than the face and hands, even if there is no fear of temptation. Furthermore, an adult should not be struck except in the case of a legal punishment (hadd) or a disciplinary one (ta'zeer).