Q4. A sand bag is dropped from a hot-air balloon that is hovering at a height of 415 feet above the ground. If air resistance is disregarded, then the distance s(t) from the ground to the sandbag after t seconds is given by s(t) = -16t2 + 415 (a) Find the velocity of a sand bag at t = 5. (b) The instant it strikes the ground. 4)