Angular motion

Question 1

What is angular motion?

Answer 1

when a body (or part of a body) moves in a circle or part of a circle about an axis of rotation

Question 2

What is the axis of rotation?

Answer 2

An imaginary line about which a body or part of a body turns

Question 3

What are the 3 main axes?

Answer 3

Longitudinal
transverse
frontal

Question 4

What is the longitudinal axis?

Answer 4

The axis passes through the centre of mass and rotates around it; diving, figure skating head to toe
from the head to the foot
of the body. Rotation around it causes the twisting action in diving, gymnastics or figure skating.

Question 5

What is the transverse axis?

Answer 5

From left to right the axis crosses through the centre of mass
rotation around it causes somersault, forward rolls

Question 6

What is the front axis?

Answer 6

front to back, the axis passes through the centre of mass and does things like kartwheels

Question 7

What is the moment of inertia?

Answer 7

Resistance/reluctance of a body to change its state of motion

Question 8

What are the two factors that affect the moment of inertia?

Answer 8

Mass of the body
Mass: the larger the mass of the body (or body part) the larger the moment of inertia; the greater the resistance to change angular
having a smaller mass
The smaller the moment of inertia of a body, the less torque is needed to change its angular motion.
The distribution of mass from the axis of toation
an increase in distance away from the axis of rotation creates an increase in inertia and decrese velocity
Arms out increases moment of inertia decreases velocity
arms in decreases moment of inertia and increases velocity

Question 9

What is the calculation of moment of inertia?

Answer 9

Mass x rotational movement
m x r2
kgm2 unit

Question 10

What is the angular velocity?

Answer 10

The rate of spin in a particular direction or angular displacement per unit of time

Question 11

How do you calculate the angular velocity

Answer 11

w (angular velocity)=displacement divided by time

measured in= rads/s

Question 12

What is the angular momentum?

Answer 12

The amount of angular motion of a rotating body

Question 13

What is the calculation for angular momentum?

Answer 13

moment of inertia x angular velocity

measured Kgm2/s

Question 14

How can angular motion be applied by newtons 1st law?

Answer 14

An object will continue to rotate with constant angular momentum unless acted upon by an external torque

Question 15

What is the law of conservation of angular motion?

Answer 15

An object in flight is not acted upon by external torques, and so angular momentum is constant.

Question 16

What happens if moment of inertia decreases during flight?

Answer 16

Velocity will increase for angular momentum to stay the same

Question 17

What is the relationship between moment of inertia and angular velocity?

Answer 17

they are inversely proportional to maintain angular momentum

Question 18

What are the factors that effect the size of the moment of inertia?

Answer 18

Mass and the distribution of mass from the axis of rotation
the greater the mass the greater the moment of inter, the lower the mass the easier it is to change the roation
distrcitubtion- the further the mass moves from the axis the greater the inter