Answer:
(a) 12 m
(b) 32 m/s
Explanation:
(a) The height of the platform is h(0) i.e. the height, h, at time t = 0 secs, since the ball would not have been thrown at that time.
Therefore, h(0) is:

The height of the platform is 12 m.
(b) The initial velocity when the baseball is thrown will be v(0) that is velocity when t = 0 secs.
We obtain velocity, v, by differentiating height, h, with respect to time:

Therefore, at time t = 0 secs:

The initial velocity of the baseball when it is thrown is 32 m/s.