Rotational MotionHard

Question

Two point masses of 0.3 kg and 0.7 kg are fixed at the ends of a rod of length 1.4 m and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The point on the rod through which the axis should pass in order that the work required for rotation of the rod is minimum, is located at a distance of : -

Options

A.0.42 m from mass of 0.3 kg
B.0.70 m from mass of 0.7 kg
C.0.98 m from mass of 0.3 kg
D.0.98 m from mass of 0.7 kg

Solution

Work required is minimum for rotation when the MI is minimum. It is minimum about that axis which pass through CM & perpendicular to the plane.
                          
C.M. from 0.3kg mass = = 0.98

Create a free account to view solution

View Solution Free
Topic: Rotational Motion·Practice all Rotational Motion questions

More Rotational Motion Questions

In the above question, if the disc executes rotatory motion, its angular acceleration will be :-...From a circular disc of radius R and mass 9 M, a small disc of mass M and radius is removed concentrically. The moment o...Two bodies A and B having same angular momentum and IA > IB, then the relation between (K.E.)A and (K.E.)B will be : ...A cubical block of side L rests on a rough horizontal surface with coefficient of friction μ A horizontal force F i...A thin uniform rod of length l and mass m is swinging freely about a horizontal axis passing through its end. Its maximu...