(adsbygoogle = window.adsbygoogle || []).push({}); I misunderstood the problem, and the answer is the correct one! sorry, and someone can close this post if necessary

1. The problem statement, all variables and given/known data

A stick of uniform density with massM = 7.9 kgand lengthL = 1 mis pivoted about an axle which is perpendicular to its length and located0.15 mfrom one end. Ignore any friction between the stick and the axle.

The stick is held horizontal and then released. What is its angular speed as it passes through the vertical.

[PLAIN]https://wug-s.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?cc/DuPage/phys2111/summer/homework/Ch-10-Rotation/pivoting_stick/5.gif [Broken]

3. The attempt at a solution

1)First I calculated the moment of inertia about the axle using the Parallel Axis Thm:

I_{total}= I_{cm}+ Md^{2}

d = 0.50 - 0.15 =>d = 0.35

I_{total}= (1/12)ML^{2}+ Md^{2}=>I_{total}= 1.626

2)I calculated the potential energy when the center of mass is at its highest point:

U=Mgh => U=Mgd =>U=27.13 J

2)When this potential energy is 0, it's kinetic energy is maximum, so:

(1/2)I_{total}w^{2}=U => w=sqrt(2U/I_{total}) =>w=5.776 rad/seg

I will appreciate any help!!!

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# Homework Help: Pivoting Stick (Rotational Dynamics)

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