A woman is reported to have fallen 144 ft from the 17th floor of a building, landing on a metal ventilator box, which she crushed to a depth of 18.0 in. She suffered only minor injuries. Neglecting air resistance, calculate
(a) The speed of the woman just before she collided with the ventilator,
(b) Her average acceleration while in contact with the box, and
(c) The time it took to crush the box.