Answer:
a = 252 m / s²
Step-by-step explanation:
The initial speed Vο = 0
The speed of baseball with witch it is thrown Vf = 42 m/s
Displacement covered = 3.5 m
Hence acceleration will be constant at this moment, so as per the equation of constant acceleration : ( Vf² - Vο² ) / 2d = a
a = 252 m / s²