What Is the Speed of a Disk's Center of Mass After Rotational Descent?

[skinnyabbey]

A uniform solid disk of radius 4.18 m and
mass 193 kg is free to rotate on a frictionless
pivot through a point on its rim.
The acceleration of gravity is 9.8 m/s2 :

If the disk is released from rest in the po-
sition shown by the solid circle, what is the
speed of its center of mass when the disk
reaches the position indicated by the dashed
circle? Answer in units of m/s.


i tried using the conservation of energy equation to solve this problem.

1/2mv^2=mgh

i used the diameter of the circle for the h, but i still couldn't find the speed of the center of mass. can anyone help?

 

[siddharth]

A uniform solid disk of radius 4.18 m and
mass 193 kg is free to rotate on a frictionless
pivot through a point on its rim.
The acceleration of gravity is 9.8 m/s2 :
If the disk is released from rest in the po-
sition shown by the solid circle, what is the
speed of its center of mass when the disk
reaches the position indicated by the dashed
circle? Answer in units of m/s.
i tried using the conservation of energy equation to solve this problem.
1/2mv^2=mgh
i used the diameter of the circle for the h, but i still couldn't find the speed of the center of mass. can anyone help?

What is "v"? Won't it be easier if you look at the motion as pure rotation about the pivoted point on the rim?