Class 11 NEET Physics System of Particles and Rotational Motion

The kinetic energy of the rolling object is converted into potential energy at height h(=

3v2

4g

)
So by the law of conservation of mechanical energy, we have

1

2

Mv2+

1

2

Iω2=Mgh

1

2

I

v2

R2

=

3

4

Mv2−

1

2

Mv2

1

2

I

v2

R2

=

1

4

Mv2
or I=

1

2

MR2
Hence, the object is disc.