In the figure,the ball $A$ is released from rest when the spring is at its natural (unstretched) length. For the block $B$ of mass $M$ to leave contact with the ground at some stage,the minimum mass of $A$ must be

Two particles with mass $m_1 = 16 \ kg$ and $m_2 = 2 \ kg$ slide as a unit with a common velocity of $12 \ ms^{-1}$ on a level frictionless surface. Between them is a compressed massless spring with spring constant $k = 100 \ Nm^{-1}$. The spring,originally compressed by $25 \ cm$,is suddenly released,sending the two masses,which are connected to the spring,flying apart from each other. The orientation of the spring w.r.t. the initial velocity is shown in the diagram. What is the relative velocity of separation in $ms^{-1}$,after the particles lose contact?

The work done in stretching a spring of natural length $25 \ cm$ and spring constant $50 \ Nm^{-1}$ from $50 \ cm$ to $60 \ cm$ is (in $J$)

$A$ block of mass $m$ is pushed against a spring with spring constant $k$ which is attached to a wall. The block slides on a frictionless table as shown in the figure. The natural length of the spring is $\ell_0$ and it is compressed to half of its natural length when the block is released. What will be the final velocity of the block?

$A$ massless platform is kept on a light elastic spring as shown in the figure. When a sand particle of mass $0.1 \; kg$ is dropped on the pan from a height of $0.24 \; m$,the particle strikes the pan and the spring is compressed by $0.01 \; m$. From what height should the particle be dropped to cause a compression of $0.04 \; m$ (in $; m$)?

$A$ spring is stretched by a distance $s$,and the potential energy stored in it is $10 \ J$. What is the work done to stretch the spring by an additional distance $s$ (in $J$)?