Question

(d) A coin rolls on a horizontal plane. What fraction of its total kinetic energy is rotational?

Answer 1

Answer:

In this type of question calculate the expression for moment of inertia I and that helps in identifying the body

Rotational KE=12Iω2

Translational KE=12Mv2

∴ Total KE=12Iω2+12Mv2

Given, 25=Rotational KETotal KEor25=(1/2)Iω2(1/2)Iω2+(1/2)Mv2

For pure rolling put v=ωRor25=Iω2Iω2+Mω2R2

∴I=2MR23

So, the rolling body is hollow sphere.

Explanation:

hope it's helpful