section_path: Revisions of the force concept
section_name: Revisions of the force concept
paragraph_text: Revisions of the force concept
  
  At the beginning of the 20th century, new physical ideas emerged to explain experimental results in astronomical and submicroscopic realms. As discussed below, relativity alters the definition of momentum and quantum mechanics reuses the concept of "force" in microscopic contexts where Newton's laws do not apply directly.