$A$ spring,when stretched by $2 \,mm$,has a potential energy of $4 \,J$. If it is stretched by $10 \,mm$,its potential energy will be:

As per the given figure,two blocks each of mass $250\,g$ are connected to a spring of spring constant $2\,N/m$. If both are given velocity $V$ in opposite directions,then the maximum elongation of the spring is:

$A$ smooth track extends to a horizontal part as shown in the figure. $A$ spring with a force constant of $400 \ N/m$ is firmly attached to one end of this horizontal part. $A$ mass of $40 \ g$ is released from a height of $4.9 \ m$. Calculate the compression in the spring in $cm$.

If a long spring is stretched by $0.02\, m$,its potential energy is $U$. If the spring is stretched by $0.1\, m$,then its potential energy will be

An elastic string of unstretched length $L$ and force constant $k$ is stretched by a small length $x$. It is further stretched by another small length $y$. The work done in the second stretching is

$A$ block of mass $m$ moving at a speed $v$ compresses a spring through a distance $x$ before its speed becomes one fourth. Find the spring constant of the spring.