The derivative of the function is:
\[ f'(t) = -5 \cdot \frac{\sqrt{6}}{t^6} \]
Evaluating this at \( t = 2 \):
\[ f'(2) = -5 \cdot \frac{\sqrt{6}}{64} \]
\[
\boxed{f'(t) = -5 \cdot \frac{\sqrt{6}}{t^6}}
\]
\[
\boxed{f'(2) = -5 \cdot \frac{\sqrt{6}}{64}}
\]