Answer:

Explanation:
For the first mass we have
, and for the second
. The pulley has a moment of intertia
and a radius
.
We solve this with conservation of energy. The initial and final states in this case, where no mechanical energy is lost, must comply that:

Where K is the kinetic energy and U the gravitational potential energy.
We can write this as:

Initially we depart from rest so
, while in the final state we will have both masses moving at velocity <em>v</em> and the tangential velocity of the pully will be also <em>v</em> since it's all connected by the string, so we have:

where we have used the rotational kinetic energy formula and that 
For the gravitational potential energy part we will have:

We don't know the final and initial heights of the masses, but since the heavier,
, will go down and the lighter,
, up, both by the same magnitude <em>h=1.25m </em>(since they are connected) we know that
and
, so we can write:

Putting all together we have:

Which means:
