**Answer:**

C. her moment of inertia increases and her angular speed decreases

D. her moment of inertia increases and her angular speed decreases

**Explanation:**

The moment of inertia of a body is the sum of the products of an increment of mass and the square of its distance from the center of rotation. When a spinning person extends her arms, part of her mass increases its distance from the center of rotation, so increases the moment of inertia.

The kinetic energy of a spinning body is jointly proportional to the moment of inertia and the square of the angular speed. Hence an increase in moment of inertia will result in a decrease in angular speed unless there is a change in the rotational kinetic energy.

This effect is used by figure skaters to increase their spin rate by drawing their arms and legs closer to the axis of rotation. Similarly, they can slow the spin by extending arms and legs.

When the person extends her arms, **her moment of inertia increases and her angular speed decreases**.

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<em>Note to those looking for a letter answer</em>

Both choices C and D have identical (correct) wording the way the problem is presented here. You will need to check carefully the wording in any problem you may think is similar.

**Answer:**

Edouard> Francesca> Avishka> Berenice> Chanwick> Danya

Para el point of the far vision (hyperopic)

Edouard > Berenica > Chdwick > Francesca = Avishka = Danya

Internal energy<span> is defined as the </span>energy<span> associated with the random, disordered motion of molecules. It is denoted by U and calculated by the expression:

</span>Δ<span>U = Q - W

We calculate as follows:

</span>ΔU = 68 J - 32 J

**ΔU = 36 J**

The amount of gravitational potential energy acquired by the rock is equal to:

where

m is the mass of the rock

g is the gravitational acceleration

is the increase in height of the rock

Substituting the data of the problem, we find

So, Natalie gave 220.7 J of energy to the rock.

I THINK 5 is A and 6 is C