- #1
anelmarx
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Homework Statement
A thin rod of length 1.50m is oriented vertically, with its bottom end attached to the floor by means of a frictionless hinge. The mass of the rod may be ignored compared to the mass of an object fixed to the top of the rod. The rod, starting from rest, tips over and rotates downward.
Find the angular speed of the rod just before it strikes the floor.
Homework Equations
KE=PE
Iw*w/2=mgh where h=L/2=CG
I=mr*r
The Attempt at a Solution
w=?
r=1.5m=L
g=6.50 rad/s*s
h=0.75m (CG=L/2)
s=2.36m
angle=90degrees=pi/2 rad
T=14.7
mr*r*w*w/2=mgL/2
Cancel out m
r*r*w*w/2=gL/2
now I have calcultated g = 6.50 rad/s*s
so
1.5*1.5*w*w/2=6.5*1.5/2
1.125*w*w=4.875
w*w=4.875/1.125
w=2.00
But the correct answer is 3.61 according to textbook.
What am I doing wrong?
Please help, I am so frustrated.