The work done in joules in increasing the extension of a spring of stiffness $10\, N/cm$ from $4\, cm$ to $6\, cm$ is:

Initially spring in its natural length now a block at mass $0.25 \,kg$ is released than find out maximum force by system on floor ? (in $N$)

Pulley and spring are massless and the friction is absent everwhere. $5\, kg$ block is  released from rest. The speed of $5\, kg$ block when $2\, kg$ block leaves the contact  with ground is (take force constant of the spring $K = 40\, N/m$ and $g = 10\, m/s^2)$

A ring of mass $m$ is attached to a horizontal spring of spring constant $k$ and natural length $l_0$ . Other end of spring is fixed and ring can slide on a smooth horizontal rod as shown. Now the ring is shifted to position $B$ and released, speed of ring when spring attains it's natural length is

A spring $40 \,mm$ long is stretched by the application of a force. If $10 \,N$ force required to stretch the spring through $1 \,mm$, then work done in stretching the spring through $40\, mm$ is ............. $\mathrm{J}$

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 is attached on the back of $m_2$ . The maximum compression of the spring will be ............... $\mathrm{m}$