$A$ spring with a spring constant of $5 \times 10^3 \ N/m$ is initially in its natural state. It is stretched by $5 \ cm$. How much work is required to stretch it by another $5 \ cm$?

$A$ massless spring of force constant $K$ is placed between two blocks of masses $m$ and $M$ on a frictionless table and compressed by an amount $x$. Upon releasing the spring,both blocks move in opposite directions. The blocks lose contact with the spring when it reaches its natural length. The speed of the block of mass $M$ at the moment of separation is:

Two springs of spring constants $K$ and $2K$ are stretched by the same force. If $W_{1}$ and $W_{2}$ are the energies stored in them respectively,then:

$A$ spring has a spring constant $200 \,N/m$. If it is stretched by $1 \,cm$, then the potential energy stored in it is: (in $\,J$)

$A$ block of mass $m$ is hung vertically from an elastic thread of force constant $\frac{2mg}{a}$. Initially,the thread is at its natural length and the block is allowed to fall freely. The work done on the block by the Earth when it passes through the equilibrium position will be:

$A$ bungee jumper is jumping with the help of an elastic ideal rope (force constant $K$). The jumper steps off the bridge and falls from rest towards the river below. He does not hit the water. The mass of the jumper is $m$,and the natural length of the rope is $l$. Gravity is $g$. Assuming everything is ideal,choose the incorrect option.