The given plot shown the variation, the potential energy $\left(U\right)$ of interaction between two particle with the separating distance $\left(r\right)$ between them. Which of the above statements are correct?

(1) $B$ and $D$ are equilibrium points 

(2) $C$ is a point of stable equilibrium points 

(3) The force of interaction between the two particle is attractive between points $C$ and $D$ and repulsive between points between $D$ and $E$ on the curve.

(4) The force of interaction between the particles is repulsive between points $E$ and $F$ on the curve.

A weight is hung freely from the end of a spring. A boy then slowly pushes the weight upwards until the spring become slack. The gain in gravitational energy of the weight during this process is equal to:

A block attached to spring, pulled by a constant horizontal force $F$, is kept on a smooth surface as shown in the figure. Initially, the spring is in its natural state. Then the maximum positive work that the applied force $F$ can do is :[ Given that spring does not break]

In a simple pendulum, the breaking strength of the string is double the weight of the bob. The bob is released from rest when the string is horizontal. The string breaks when it makes an angle $\mathrm{\theta }$ with the vertical: