Answer to other questions:
After the accident, American Airlines examined runway 31L and documented a left main landing gear tire mark that was 564 ft long, a right main landing gear tire mark that was 216 ft long, and a scrape mark from the left wingtip that was 323 ft long. The wingtip scrape marks began to the left of the runway edge marking and extended to the edge of the paved surface. The airplane’s left wing impacted a distance remaining marker on the left edge of the paved runway surface
Means the scraping lasted for around 1.25 seconds.