Question

A solid cylinder of length 1 m and diameter of cross section y 100 cms is first placed with its axis vertical its then slowly inclined till its axis is horizontal. The loss in its potential energy if the mass of the cylinder is 10 kg is (a) 5g J (b) 10g J (c) Zero (d) g J​

Answer 1

Answer:

Their kinetic energies at the bottom will be

2

1

mv

2

+

2

1

Iω

2

=

2

1

mv

2

+

2

1

kmr

2

r

2

v

2

=

2

1

mv

2

(1+k) The velocity would be greater for the material with radius of gyration k is lower of for which the moment of inertia is lower. Solid cylinder with k as 1/2 will have greater velocity as compared to hollow cylinder which has k as 1. As as they have same mass and radius their energies at both the levels would remains same including the potential energy and energy lost due to friction. Thus both option B and D are correct.