Respuesta :
The correct answer is
D.) 2300 N up
In fact, the normal force is the reaction force exerted by the surface on the object, perpendicular to the surface itself, equal and opposite to the weight of the object.
Therfore, the magnitude of the normal force is equal to the weight of the object:
[tex]N=W=mg=(230 kg)(10 m/s^2)=2300 N[/tex]
And since the weight is downward, the normal force is upward.