Angular motion

Question 1

what plane and axis does angular motion take place

Answer 1

transverse plane and longitudinal axis

Question 2

what is torque

Answer 2

the force that allows us to rotate

Question 3

what is angular displacement

Answer 3

the smallest change in angle between start and finish points of a rotation

measured in degrees and radians

Question 4

what is angular velocity

Answer 4

the rotational speed of an object

refers to the rate of change of angular displacement

Question 5

what is angular acceleration

Answer 5

the rate of change of angular velocity

Question 6

newtons 1st law of angular motion

Answer 6

a rotating body will continue with constant torque until a large enough external force acts upon it

e.g.
- ice skater spinning: external force the ice

Question 7

newtons 2nd law of angular motion

Answer 7

The rate of change of angular momentum is proportional to the torque applied, and occurs in the direction of the torque.

Formula: τ = I × α
(τ = torque, I = moment of inertia, α = angular acceleration)

e.g.
- Diver rotating during a somersault: The more torque the diver applies at takeoff (e.g. by pushing off the board and tucking tightly), the greater their angular acceleration, allowing them to rotate faster in the air.

Question 8

newtons 3rd law of angular motion

Answer 8

when torque is applied, there will always be an equal and opposite force

e.g.
- Swimmer using flip turn: When a swimmer pushes against the wall with their feet to rotate into the next length, the wall exerts an equal and opposite torque on the swimmer, helping them twist and change direction underwater.

Question 9

what is angular momentum (graph)

Answer 9

remains constant at all times

therefore as inertia increases, angular velocity must decrease - contrasting relationship

what’s in the graph:
- angular velocity
- angular momentum
- moment of inertia