\[ U = 2x^2 + 3y^3 + 2z \]
The force in the \(x\)-direction is given by \(F_x = -\frac{\partial U}{\partial x}\). Differentiating \(U\) with respect to \(x\):
\[ F_x = -\frac{\partial}{\partial x}(2x^2) = -4x \]
Substitute \(x = 1\):
\[ F_x = -4 \times 1 = -4 \]
The magnitude of \(F_x\) is 4 N.
So, the correct answer is: 4 N