Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force F(x) acts on it. Suppose that $$E_{mech} = 8$$ J, the incorrect statement for this system is:

$$E_{\text{mech}} = K + U = 8\ \text{J}$$ $$\implies K = 8 - U$$

Check Option A:

$$\text{For } x > x_4: U = 6\ \text{J} \implies K = 8 - 6 = 2\ \text{J}\ (\text{constant})$$

Check Option B:

$$\text{For } x < x_1: U = 8\ \text{J} \implies K = 8 - 8 = 0\ \text{J}\ (\text{particle is at rest})$$

Check Option C:

$$\text{At } x = x_2: U = 0\ \text{J} \implies K_{\text{max}} = 8 - 0 = 8\ \text{J}\ (\text{fastest speed})$$

Check Option D:

$$\text{At } x = x_3: U = 4\ \text{J} \implies K = 8 - 4 = 4\ \text{J}$$