Question

Two planks each of mass $m$ and length $L$ are connected by a frictionless, massless hinge as shown in the figure. Initially the system is at rest on a level frictionless surface. The vertical plank falls anticlockwiese and finally comes to rest on the top of the horizontal plank. Find the displacement of the hinge till the two planks come in contact.

Answer 1

$M_{com}=\frac{m_1\times x_1+m_2{n}_2}{m_1+m_2}$
$M_{com}=\frac{m\times 0+m\times \frac{L}{2}}{2m}=\frac{L}{4}$
$x_{Me}$ $x=\frac{L}{4}$