It would be: Speed = Distance / Time
Reaction force is the ball pulling up on the Earth. Every action has an equal and opposite reaction, so when the Earth pulls on the baseball, the baseball pulls back on the Earth with equal force
Is there a multiple choice?
(a) 3675 N
Assuming that the acceleration of the rocket is in the horizontal direction, we can use Newton's second law to solve this part:

where
is the horizontal component of the force
m is the mass of the passenger
is the horizontal component of the acceleration
Here we have
m = 75.0 kg

Substituting,

(b) 3748 N, 11.3 degrees above horizontal
In this part, we also have to take into account the forces acting along the vertical direction. In fact, the seat exerts a reaction force (R) which is equal in magnitude and opposite in direction to the weight of the passenger:

where we used
as acceleration of gravity.
So, this is the vertical component of the force exerted by the seat on the passenger:

and therefore the magnitude of the net force is

And the direction is given by

I think it is high pressure / gravity and high temperatures