Answer
$-3.73J$
Work Step by Step
Potential energy at $x=5m$
$U(x) = -4xe^{^{\frac{-x}{4}}}$
$= -4 \times (5) \times e^{^{\frac{-5}{4}}}$
$= -20 \times e^{^{\frac{-5}{4}}}$
$= -5.73J$
Then, finding the mechanical energy of the system:
$E = K + U(x) $
$= 2J -5.73J$
$=-3.73J$
