A massless platform is kept on a light elastic spring as shown in fig. 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 spring is compressed by $0.01\; m$.

From what height should the particle be dropped to cause a compression of $0.04\; m$.

A block of mass $m$, lying on a smooth horizontal surface, is attached to a spring (of negligible mass) of spring constant $k$. The other end of the spring is fixed, as shown in the figure. The block is initially at rest in a equilibrium position. If now the block is pulled with a constant force $F$, the maximum speed of the block is

A spring of force constant $k$ is cut in two parts at its one third length. When both the parts are stretched by same amount, the work done in the two parts, will be

Two particles with mass $m_1$ = $16\ kg$ and $m_2$ = $2\ kg$ slide as 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 diagram. What is the relative velocity of separation in $ms^{-1}$ , after the particles lose contact? ................$m/s$

To simulate car accidents, auto manufacturers study the collisions of moving cars with mounted springs of different spring constants. Consider a typical simulation with a car of mass $1000\; kg$ moving with a speed $18.0\; km / h$ on a smooth road and colliding with a horizontally mounted spring of spring constant $6.25 \times 10^{3} \;N m ^{-1} .$ What is the maximum compression of the spring in $m$?

Two springs $A$ and $B$ having spring constant $K_{A}$ and $K_{B}\left(K_{A}=2 K_{B}\right)$ are stretched by applying force of equal magnitude. If energy stored in spring $A$ is $E_{A}$ then energy stored in $B$ will be