Noninertial frame projectile. A device shoots a small ball horizontally with speed 0.217 m/s from heighth-0.857 m above an elevator floor. The ball lands at distance d from the base of the device directly below the ejection point. The vertical acceleration of the elevator can be controlled. What is the elevator's acceleration magnitude a if d is (a) 14.0 cm, (b) 20.0 cm, and (c) 7.50 cm? (a) Number i 9.127 Units m/s^2 (b) Number i 9.329 Units m/s^2 (c) Number i 8.547 Units m/s^2