A steel cable supports an elevator weighing 1800 lb. Starting from rest, the elevator reaches a velocity of 10 ft/s upward in 2.5 sec. Find the tension in the cable at the 2.5-sec mark, if the same force is continued? If the cable breaks at the 4-sec mark, compute how long will it take the elevator to fall back to the surface, if it were 75 feet above it when the cable broke?