Rotational MotionMedium

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

A particle starts from the point (0m, 8m) and moves with uniform velocity of 3î m/s. After 5 seconds, the angular v...The moment of inertia of a solid cylinder of diameter D and length L about an axis perpendicular to the length and passe...A disc of radius R is rolling purely on a flat horizontal surface, with a constant angular velocity. The angle between t...A wheel initially at rest is subjected to a uniform angular acceleration about its axis. In the first 2 s it rotates thr...Three particles, each of mass m are placed at the points (x1, y1, z1), (x2, y2, z2) and (x3, y3, z3) on the inner surfac...