Please give me a detail explanation on this dynamics problem.

The system is released from rest when the angle $=90$deg. Determine the angular velocity of the uniform slender bar when $=60$deg.

Use the values:

$m1=1\mathrm{.}69kg$

$m2=2\mathrm{.}13kg$

$b=0\mathrm{.}3m$

Give your answer to two decimal places; use $9\mathrm{.}81\frac{m}{s^2}$ for g $.$

Question $2$:

What is the relationship of the magnitude of the $y$ velocity of mass $2$ to the magnitude of the tangential velocity of point A at $=19$ deg?

$y^{}=x*b{}^{}$

What is $x?$

Hint: Find the length of the rope for any angle $,$ take a derivative with respect to time to get a velocity relationship, and then plug in $.$