Question

A horizontal disc rotating freely about a vertical axis

Answer 1

HeYa❤

The moment of inertia of the disc is 2mr²

Explanation:

Let I be the moment of inertia of disc

Let I be the moment of inertia of discmoment of inertia of wax = mr²

Let I be the moment of inertia of discmoment of inertia of wax = mr²after wax falls the net moment of inertia = I + mr²

Let I be the moment of inertia of discmoment of inertia of wax = mr²after wax falls the net moment of inertia = I + mr²Since there is no external torque acting on the system, So the angular momentum of the system will remain constant.

Hope it's helps you ❤

Answer 2

Answer:

Initial angular velocity

w

1

=

90

r

e

v

/

m

i

n

Moment of inertia of the disc

=

I

k

g

−

m

2

Final angular velocity

w

2

=

60

r

e

v

/

m

i

n

Now, taking the angular momentum conservation

L

1

=

L

2

I

w

1

=

(

I

+

m

r

2

)

w

2

I

∗

90

=

(

I

+

m

r

2

)

∗

60

1.5

I

=

I

+

m

r

2

0.5

I

=

m

r

2

I

=

2

m

r

2