A uniform thin rod of mass ????=3.47 kgM=3.47 kg pivots about an axis through its center and perpendicular to its length. Two small bodies, each of mass m=0.263 kgm=0.263 kg , are attached to the ends of the rod. What must the length ????L of the rod be so that the moment of inertia of the three-body system with respect to the described axis is ????=0.907 kg·m2I=0.907 kg·m2 ?

Respuesta :

Answer:

L= 1.468 m

Explanation:

The moment of inertia of the rod about its center is (1/12)m_RL^2

The moment of inertia of each of the two bodies about the described axes is m_B(L/2)2

Hence, the moment of inertia of three body system is (1/12)m_RL^2+ 2×m_B(L/2)^2 which is given to be equal to I_T

=> L^2[(1/12)m_R+m_B/2] = I_T

=> L2 = IT/(mR/12+ mB/2)

=> L = sqrt( 12I_T/(m_R+6m_B))

now putting the value of m_R= 3.47 kg

m_B= 0.263 kg

I_T = 0.97 kg/m^2

[tex]L= \sqrt{\frac{12I_T}{m_R+6m_B} }[/tex]

[tex]L= \sqrt{\frac{12\times0.907}{3.47+6\times0.263} }[/tex]

L= 1.468 m  is the length of the rod be so that the moment of inertia of the three-body system