Turning a Straight Wire into a wheel with spokes, solve for I

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
3 replies · 7K views
gkinnish
Messages
2
Reaction score
0

Homework Statement


A stiff uniform wire of mass M_0 and length L_0 is cut, bent, and the parts soldered together so that it forms a circular wheel having four identical spokes coming out from the center. None of the wire is wasted, and you can neglect the mass of the solder.
 
Physics news on Phys.org
solving for the moment of inertia i came up with 4/3(M/(L/(2pi+4))^2)
 
gkinnish said:
solving for the moment of inertia i came up with 4/3(M/(L/(2pi+4))^2)

can you show your steps... that's not what I'm getting... some things are similar... some things are different.

The mass of each spoke is [tex]\frac{1}{2\pi + 4}*M_0[/tex]

The length of each spoke is [tex]\frac{1}{2\pi + 4}*L_0[/tex]

What's the moment of inertia of each spoke?

What's the mass of the circular section? What's the moment of inertia of the circular section?