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

1.	A metal piece of mass 120 g 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=sqrt3.24=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)`