Answer:
Explanation:
radius of hoop and the radius of disk is same = R
Let the mass of hoop is M and the mass of disk is M'.
As they reach the bottom of teh surface in same time so they travel equal distance thus, they have same acceleration.
The acceleration is given by

As the acceleration is same so that the moment of inertia is also same.
Moment of inertia of disk = moment of inertia of hoop
1/2 x mass of disk x R² = mass of hoop x R²
So, mass of disk = 2 x mass of hoop
Option (c) is correct.
Since the outer plumage of the penguin can resist the flow of heat in the cold antarctic air they might gain a little of this heat to keep them warm by thermal convection.
<u>Explanation:</u>
- Convection is the circular movement that happens when hot air/liquid moves with molecules that were fast, making it less dense rises while the cold air/liquid drops down.
- Also, they follow the technique of standing together always in a group which further helps them to decrease the loss of heat between them.
- The plumage of penguin provides 80 percent of total insulation and is highly resistant to wind penetration.