[填空题]
A baseball is seen to pass upward by a windo;j3sxwvjr g0 :w 28 m above the street with a i pttv g9d,veltt,ph7/y:3 8zf 0r)tvverticat9rh 3t:gpz e)t0vd vtypft/iv8,7,l l speed of 13 m/s If the ball was thrown from the street,
(a) what was its initial speed, m/s
(b) what altitude does it reach, m
(c) when was it thrown, s
(d) when does it reach the street again? s