Angular Kinetics ( Test 2 )

Question 1

What is angular kinetics

Answer 1

the study of angular motion with regards to force

Question 2

What is the angular analogue of mass

Answer 2

Moment of Inertia ( I )

Question 3

What is the Moment of Inertia

Answer 3

It’s an objects resistance to angular acceleration

Question 4

What are the two factors that influence ( I )

Answer 4

1. m = the mass of the object

2. k = the distribution of mass, relative to the axis of rotation

Question 5

What is k

Answer 5

The radius of gyration

Question 6

How do we find ( I )

Answer 6

set up the object as a pendulum and time how long it takes to rotate

Question 7

How does ( I ) affect rotation

Answer 7

the smaller the I the easier to rotate

Question 8

Can one manipulate their I

Answer 8

yes, not by changing their mass, but by changing k. It can be done by bringing your arms in to decrease I, or sticking them out to increase I.

Question 9

How many ( I )’s does an object have

Answer 9

3

1. Anterior/Posterior
2. Medial/Lateral
3. Long axis

Question 10

What is Newtons first law for angular kinetics

Answer 10

a rotating body will remain in a state of constant rotational motion unless acted upon by an outside torque. ( Conservation of Angular Momentum )

Question 11

What is Angular momentum

Answer 11

H = Iω = mk²ω

Question 12

In the absence of net external torque what is true about H (angular momentum)

Answer 12

It in conserved

Question 13

When angular momentum is conserved, or there is not net torque acting on the object what do we know about I and ω

Answer 13

Not much, although H is constant I and ω can change.

Question 14

What is needed for a change in angular momentum ( H )

Answer 14

torque and time

Question 15

When thinking about momentum for a projectile, what happens to the center of mass trajectory.

Answer 15

It doesn’t change, it’s still subject to gravity

Question 16

Although angular momentum is conserved while the body is airborne, can it be transfered from one segment to another.

Answer 16

Yep, but momentum for one segment will increase and the momentum for the other will decrease proportionally

Question 17

Can one even change the direction of rotation while airborne

Answer 17

yep

Question 18

What is newtons 2nd law for angular kinetics

Answer 18

Torque causes angular acceleration, ( and ∆H )

ΣT = I α

Question 19

How can a person change Momentum ( H )

Answer 19

an external force

Question 20

What is angular impulse

Answer 20

Torque over a period of time ( torque x time )

Question 21

What is newtons 3rd law for angular kinetics

Answer 21

For every torque exerted by one body on another there is an equal ( in size ) and opposite ( in direction ) torque exerted on the second body by the first body.

Question 22

Know the two tables under angular kinetics

Answer 22

ok