A metal piece of mass 120g is stretched to form a plane rectangular sheet of area of cross section 0.54m^(2). If length and breadth of this sheet are in the ratio 1:6, find its moment of inertia about an axis passing through its centre and perpendicular to its plane.

A metal piece of mass 120g is stretched to form a plane rectangular sh

1.	A metal piece of mass 120g is stretched to form a plane rectangular sheet of area of cross section 0.54m^(2). If length and breadth of this sheet are in the ratio 1:6, find its moment of inertia about an axis passing through its centre and perpendicular to its plane.
Answer» SOLUTION :Mass `M=120g=120xx10^(-3)kg` area `=lb=0.54m^(2)` `(l)/(b)=(1)/(6)` `:.l=(b)/(6)` `lb=0.54`, `(b)/(6).b=0.54` `b^(2)=0.54xx6impliesb=sqrt(3.24)=1.8m` SIMILARLY `l=(0.54)/(1.8)=0.3m` Moment of Inertia `I=(M(l^(2)+b^(2)))/(12)=(120xx10^(-3)[(0.3)^(2)+(1.8)^(2)])/(12)` `I=33.3xx10^(-3)kgm^(2)`