$A$ ball of mass $m$ falls from a height $h$ onto a platform attached to a vertical spring. The platform is displaced by a distance $x$. What is the spring constant?

Two masses $m_1 = 2\,kg$ and $m_2 = 5\,kg$ are moving on a frictionless surface with velocities $10\,m/s$ and $3\,m/s$ respectively. An ideal spring with spring constant $K = 1120\,N/m$ is attached to the back of $m_2$. The maximum compression of the spring will be ............... $m$.

The force constants of two springs are $K_1$ and $K_2$. Both are stretched until their elastic potential energies are equal. If the stretching forces applied are $F_1$ and $F_2$,then the ratio $F_1:F_2$ is:

$A$ block of weight $W$ moving with velocity $v$ on a frictionless horizontal surface hits a spring of force constant $k$. The maximum compression in the spring will be at a distance of .........

$A$ mechanical system consists of two springs with stiffness coefficients $k_1$ and $k_2$ connected in series. The minimum work to be performed on the system to stretch it by a total displacement $\Delta$ is

$A$ ball of mass $m$ is dropped from a height $h$ on a platform fixed at the top of a vertical spring,as shown in the figure. The platform is depressed by a distance $x$. Then the spring constant is