ANgular kinetics

Question 1

What is angualr kinetics?

Answer 1

causes of angular motion

Question 2

WHat is angular (rotary inertia). QUnatified as?

Answer 2

– property of an object to resist changes in its angular motion.
- moment of inertia (I)

Question 3

is moment of inertia scalar or vector?

Answer 3

scalar

Question 4

what is SI unit for moment of inertia

Answer 4

kg x m^2

Question 5

What is the ri in the moment of inertia equation

Answer 5

radius frolm particle i to axis of rotation a

Question 6

what is the radius of gyration?

Answer 6

the distance from the axis of rotation to the point at which an objects mass could be concentrated without changing angular inertia of an object

Question 7

What is the differnencce between linear and angular inertia

Answer 7

linear inertia is dependent only on mass while angular is dependent on mass and distribution of mass (r or k)

Question 8

What is Ka? What is r? in angular inertia

Answer 8

ka is radius of gyration about axis a
r is radius (distance) from particle i to axis of rotation ‘a’

Question 9

An object free to rotate will rotate about what?

Answer 9

Its CG

Question 10

what is an eccentric axis/when does it occur

Answer 10

Not thru an objects CG, occurs in objects that we swing as they have an axis of rotation thrust upon them

Question 11

Why can objects have multiple moments of Inertia?

Answer 11

becuase they can rotate abtout many diffenect axes

Question 12

What is angular inertia dependent on?

Answer 12

mass and distribution of mass (r or k)

Question 13

Whats greater the moment of inertia about axis b or about the centre of gravity?

Answer 13

axis b

Question 14

What are the 3 different axes which it is possible to have moments of inertia?

Answer 14

anteroposterior (saggital), longitudianl (vertical), transverse (frontal)

Question 15

How many moments of inertia can each axes have?

Answer 15

1

Question 16

Can the moment of our body change the moment of inertia, why?

Answer 16

yes it can because our body is not rigid and the cg changes

Question 17

linear velocity ____ as distance from axis of rotation increases

Answer 17

increases

Question 18

as implement length increases moment of intertia ____ which makes it _____ to accelarate the object to achieve the same angular velocity

Answer 18

also increasess so it makes it harder to accelrate

Question 19

What is H

Answer 19

angular momentum

Question 20

What does angular momentum quantify?

Answer 20

the angular motion of an object

Question 21

is angular momentum scalar or vector?

Answer 21

vector?

Question 22

what is the si unitu for angular momentum?

Answer 22

kgxm/s^2

Question 23

For rigid objects what is angular momentum dependeont on?

What about for non-rigid objects?

Answer 23

for rigid objects it depns only on w (angular velocity) not moment of inertia bc it remains constant

For non-rigid it depends on both moemnt of inertia and angular velocity

Question 24

Do distribution of mass and mass have the same effect on linear inertia?

Answer 24

no. distirbution of mass can change and has a greater effect than the mass on linear inertia

Question 25

In a symmetrical acitvity what is the total angular moemntum of the body?

Answer 25

0 - equal and opposture for left/roght arms and legs 0 momentun for trunk bc its not rotating

Question 26

How dose angular momentum relate to newtons first law?

Answer 26

angular momentum of an object remains constant unless a net external torque acts on it for a rigid body where I is constant the angukar velocity must also be constant For a non-rigid body, it isn’t necessary for angular velocity to be constant – only that I × ω remains constant if no external torques ac

Question 27

what is net torque according to coservation of angukar momentum?

Answer 27

0

Question 28

How does angular momentum relate to newtons second law

Answer 28

Change in angular momentum of an object is proportional to net external torque acting on it and in the direction of the torque

Question 29

Angular accelation will be ____ porportonal to torque and _____ porpotional to its moemtn of inertia

Answer 29

directly, indierectly

Question 30

according to law of acceleratio, net external torque exerted on an object is ____ to the rate of change on angular momentum

Answer 30

porportional

Question 31

What are three ways that changes in angular momentum may be seen as

Answer 31

- speeding up or slowing down of angular velcoty change in direction of the axis of rotation change in the moment of inertia

Question 32

what is angular impulse

Answer 32

change in angular momentum over time

Question 33

torque application can be prolonged by starting with a ____ moment of inertia and ____ to increase ___

Answer 33

stary w large moment of inerta and decrease it to increase angular velocity

Question 34

How does angular momentum relate to Newtons 3rd law

Answer 34

for every torque eexerted on an object exerts an equal and opposite torque on the first object