A boy jumps off a high diving board above a swimming pool. Halfway between the board and the water he tosses a ball up-ward. Ignoring air friction, the instant after the ball leaves his hands the vertical component of the acceleration of the ball(A) is positive, but then decreases through zero to -9.8 m/s2.(B) is zero, but then decreases to – 9.8 m/s2.(C) is between zero and -9.8 m/s2, but then decreases to -9.8 m/s2.

The correct option is: (A) is positive, but then decreases through zero to -9.8m/s².
Assume that the boy tosses up the ball by imparting a vertical initial acceleration of magnitude a in the upward direction. If the magnitude of a is greater than g, the ball would have an initial positive acceleration.

As the magnitude of a would decrease over time and become zero, the net acceleration of ball would also decrease, pass through zero and eventually reach to . – 9.8 m/s²
Therefore, the correct option is (a), while the rest are ruled out.