Answer:
A) I = 20 N s
, B) F = 7.92 N
Step-by-step explanation:
A) The momentum is
I = F Δt 
 calculate 
I = 50 0.40 
I = 20 N s 
B) The momentum is related to the change of the moment of the system 
I = Δp 
F Δt = m 
 - m v₀
 - m v₀
in this case we must assume that the initial velocity is very small, vo = 0 
F = m v_{f} / Δt 
calculate 
F = 0.11 36 / 0.5 
F = 7.92 N