Respuesta :
F = (mass)(acceleration) = ma
m = 0.25 kg
Vi = 16 m/s
t = 2 s
Vf = 0 m/s (since it was put to stop)
a=(Vf-Vi)/t
a=(0-16)/2
a = 8 m/s^2 (decelerating)
F = ma = (0.25 kg)(8 m/s^2)
F = 2 N
Hope this answer will be a good help for you.