Four particles A, B, C and D of mass 2 kg, 5 kg, 6 kg and 3 kg respectively are rigidly joined together by light rods to form a rectangle ABCD where AB=2a and BC=4a. Find the moment of inertia of this system of particles about an axis along:
a) AB

b) BC

c) AC

d) through the midpoints of AB and CD

Question

Four particles A, B, C and D of mass 2 kg, 5 kg, 6 kg and 3 kg respectively are rigidly joined together by light rods to form a rectangle ABCD where AB=2a and BC=4a. Find the moment of inertia of this system of particles about an axis along:
a) AB                                
 
b) BC                     

c) AC      
                  
d) through the midpoints of AB and CD

.sam. · Answer

$$I=mr ^{2}$$

anonymous · Answer

thank you..but, still not helping..i got that a lot in my note and book..

.sam. · Answer

AB, 
I=(6+3)(4a)^2 using formula mr^2

anonymous · Answer

there u are..does for D, I=(mL^2)/3..then (3+2)(2a)^2/3..=(20a^2)/3..does the question mean that the answer will be unknown?

anonymous · Answer

|dw:1330093965825:dw|
as moment of inertia for a particle is
I=mr 2 
about ab means look at other masses other than aand b