FACT: An organism's kingdom does not only describe physical characteristics.
Organisms are classified into the different kingdoms based on physical appearance, their function, how they reproduce and how they obtain their food.
EVIDENCE:
Kingdom Plantae: They obtain their food through photosynthesis
Reproduce asexually.
Kingdom Animalia : They obtain their food through hunting or consuming other organisms.
Reproduce sexually.
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.
How fast a car goes is known as its speed.
Speed = (distance covered) divided by (time to cover the distance)
It has nothing to do with the direction the car is going.
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The car's velocity is its speed AND the direction it's going.
30 miles per hour . . . speed
40 miles per hour north . . . velocity
20 miles per hour south
20 miles per hour west . . . . . same speed, different velocity
-- 'Velocity' is NOT a big word that you use when you mean
'speed' but you want to sound smarter. It's a different thing.
-- If you don't know anything about the direction the car is going,
then you can't say anything about its velocity.
-- If the car is going around a curve, then its velocity is constantly
changing, even if its speed is constant.
