The points of maximum and minimum attraction in the curve between potential energy $(U)$ and distance $(r)$ of a diatomic molecule are respectively:

Is the work done by non-conservative forces always negative? Discuss.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: In a central force field,the work done is independent of the path chosen.
Reason $R$: Every force encountered in mechanics does not have an associated potential energy.
In the light of the above statements,choose the most appropriate answer from the options given below:

The potential energy of a certain particle is given by $U = \frac{1}{2}\,(x^2 - z^2)$. The force on it is:

$A$ body with mass $2\, kg$ moves in one direction in the presence of a force which is described by the potential energy graph. If the body is released from rest at $x = 2\, m$,then its speed when it crosses $x = 5\, m$ is ................ $m/s$.

In the case of non-conservative forces,the following statement is correct.