Question

an
Moment of intertia of
about
aring
axis
centre
passing through its
and
per pendicolao to its plane is
100 kg M? It is rotates with a frequency of 60rpm calculate the. rotational kinetic energy of the ring​

Answer 1

Explanation:

Initial angular momentum, L

1

=Iω

K

1

=

2

1

Iω

2

When, second ring is put on it and they start rotating with same angular speed, say ω

o

.

Now, final angular momentum, L

2

=2Iω

o

Conservation of angular momentum:-

L

1

=L

2

⟹Iω=2Iω

o

⟹ω

o

=

2

ω

K

2

=2×

2

1

Iω

o

2

=Iω

o

2

K

2

=

4

1

Iω

2

⟹K

1

−K

2

=

4

1

Iω

2

Hence, answer is option-(B).