Question

to block each of mass M moving with equal speed v in opposite directions strike the opposite ends of massless spring place in between them if K is the force constant of the spring the maximum compression of the spring is

Answer 1

$2 \times \frac{1}{2} \times m \: v {}^{2} = \frac{1}{2} kx { {}^{} }^{2}$
where x is elongation in spring