Question

A particular trophy has a solid 0.2m radius base with a mass of 1.2kg. Rising up from the center is a 0.01m radius solid rod with a mass of 0.4kg. Centered on top of this is a hollow sphere with a radius of 0.15m and a mass of 0.8kg. Calculate the total moment of inertia for this trophy around the vertical axis.

Answer 1

m1=1.2 kg, r1=0.2 m, - cylinder: J1=m1•r1²/2
m2 = 0.4 kg, r2=0.01 m – cylinder: J2=m2•r2²/2
m3=0.8 kg r3=0.15 m – hollow sphere: J3= 2m3•r3²/3

J=J1+J2+J3 = ...