 #1
spsch
 111
 21
 Homework Statement:

With what speed does the tip of a 25meter high tree hit the ground?
Assume the tree has a moment of inertia of a long thin rod.
 Relevant Equations:
 ## mg* \frac {l}{2} = \frac {1}{6} *m*l^2 * (\frac {v^2} {l^2}) ##
Hi, I am still working on the same exams problems, the second last one is giving me a bit of a headache after I found this https://physics.stackexchange.com/q...ranuprightrigidbodytofalltotheground which contradicts my solution.
Can I assume that when the tree hit's the ground all of it's potential energy is converted to rotational energy?
I was thinking this is why they mention the moment of inertia being that of a long thin rod.
So I went with:
## mg* \frac {l}{2} = \frac {1}{6} *m*l^2 * (\frac {v^2} {l^2}) ##
and got: v= ## \sqrt {3*g*l} ##
Can I assume that when the tree hit's the ground all of it's potential energy is converted to rotational energy?
I was thinking this is why they mention the moment of inertia being that of a long thin rod.
So I went with:
## mg* \frac {l}{2} = \frac {1}{6} *m*l^2 * (\frac {v^2} {l^2}) ##
and got: v= ## \sqrt {3*g*l} ##