Question: the free surface of a rotating fluid is
[{'answer': 'a paraboloid', 'provenance': [{'wikipedia_id': '14463033', 'title': 'Free surface', 'start_paragraph_id': 13, 'start_character': 202, 'end_paragraph_id': 13, 'end_character': 214, 'bleu_score': 1.0, 'section': 'Section::::Rotation.\n'}]}, {'provenance': [{'wikipedia_id': '14463033', 'title': 'Free surface', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 523, 'bleu_score': 0.979054689945215, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10533156081326907493}, 'section': 'Section::::Rotation.\n'}]}]