Answer:
a)  a = 91.4 m / s²,  b)   t = 0.175 s, c) Â
Explanation:
a) This is a kinematics exercise
      v² = vox ² + 2a (x-xo)
      a = v² - 0/2 (x-0)
     Â
let's calculate
     a = 16² / 2 1.4
     a = 91.4 m / s²
b) the shooting time
     v = vox + a t
     t = v-vox / a
     t = 16 / 91.4
     t = 0.175 s
c) let's use Newton's second law
     F = ma
     F = 7.9 91.4
     F = 733 N