Question

What net force would be needed to accelerate the box at 2.3 m/s^2

Answer 1

The pertinent equation here is F=ma.  You haven't shared the mass of the box, so I will use M to represent that mass.

Then F = M(2.3 m/s^2)        (answer)

Answer 2

The required force, in newtons, is

(2.3) x (the mass of the box, in kilograms) .