Answer:
F = 30 N Directed up
Explanation:
We can solve this problem using the momentum and momentum relationship.
I = ΔP
I = ∫ F dt
As we are asked for the average force, that leaves the integral, giving
I = F t
F t = m [tex]v_{f}[/tex] - m v₀
F = m ([tex]v_{f}[/tex]-v₀) / t
Note that, if you define the upward positive direction, the initial velocity is negative
Let's calculate
F = 0.15 (3.5 - (-6.5)) / 0.050
F = 30 N
Directed up