Net Force problem?

Question

If it takes a human cannonball 1.5 s to exit a 1.6 m long cannon, what is the average net force acting on the performer if his mass is 65 kg?

Answer 1

Considering, s=ut + 0.5at^2
where, s=distance, u=initial velocity, t=time taken and a is the average acceleration.

s=1.6, u=0, t=1.5s; therefore solving for a, a=1.422 m/s^2

F = m*a =65*1.422 = 92.4 N