Question

If the angular velocity of a body rotating about a
given axis is doubled, then its rotational K.E
(A) is doubled.
(B) is halved.
(C) becomes four times.
(D) becomes one-fourth.​

Answer 1

Answer:

Initially

W

1

=angular velocity

I

1

=Moment of inertia

Rotational kinetic energy

K

1

=1/2I

1

W

1

2

Finally

W

2

/I

2

W

2

=2W

1

/I

2

=

2

I

1

K.E.

K

2

=1/2I

2

W

2

2

=

2

1

×

2

I

1

×4W

1

2

k

2

=2k

1

.