Three point masses m1,m2,m3 are located at the vertices of an equilateral triangle of length 'a'. The moment of inertia of the system about an axis along the altitude of the triangle passing through m1, is:-
moment of inertia is the product of mass and square of separation between particle and axis of rotation .
e.g , M.I=mr²
here, we see, separation of mass m1 and altitude NN′is 0 .
alteration between mass m2 andNN′ is (a2) also for m3 separation is (a2)
moment of inertia about altitude passing through m1=I1+I2+I3
where I1,I2,and I3 are M.Iof m1,m2and m3 respectively .
M.I=m1.(0)+m2(a2)2+m3(a2)2
=a24×(m2+m3)