\textbf{50.} The equation of motion of an object with mass $500\,\text{g}$ moving along the $x$-axis is, in SI units, $\vec{F} = (6 - 3t)\hat{i}$. The net average force exerted on this object during the time interval $t_1 = 1\,\text{s}$ to $t_2 = 3\,\text{s}$, in newtons, is:
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(1) $3\hat{i}$ \hspace{1.5cm} (2) $-3\hat{i}$ \hspace{1.5cm} (3) $6\hat{i}$ \hspace{1.5cm} (4) $-6\hat{i}$
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\textit{Space for calculations}
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