5.4 Angular motion

Question 1

Newtons first law of angular motion

Answer 1

A rotating body will continue in a state of angular rotation unless a torque acts upon it

Question 2

Newtons second law of angular motion

Answer 2

The rate of change of angular momentum of a body is proportional to the torque causing it and the direction in which the torque is applied

Question 3

Newtons third law of angular motion

Answer 3

For every torque, there is an equal and opposite reaction torque.

Question 4

Define angular displacement

Answer 4

The smallest change in angle between the starting and finishing point of the rotation

Question 5

Units for angular displacement

Answer 5

Radians (rad). 1 radian = 57.3 degrees

Question 6

Define angular velocity

Answer 6

The rate of change of angular displacement.
Angular displacement/time (s)

Question 7

Units for angular velocity

Answer 7

Radians per second (rad/s)

Question 8

Define angular acceleration

Answer 8

The rate of change of angular velocity.
Change in angular velocity/time taken

Question 9

Units for angular acceleration

Answer 9

radians per second squared
(rad/s2)

Question 10

Describe the relationship between moment of inertia and angular velocity

Answer 10

inversely proportional

Question 11

What is moment of inertia and what does it depend on

Answer 11

moment of inertia is the resistance of a body to change its state of angular motion.
It depends on an objects mass and the distribution of mass away from the axis of rotation

Question 12

Affect of a greater mass on moment of inertia

Answer 12

greater moment of inertia

Question 13

What is angular momentum

Answer 13

The quantity of rotation a body possess

Question 14

How could a figure skater increase their speed of rotation

Answer 14

Bring arms in toward axis of rotation to reduce moment of inertia. Reduction of moment of intertia means angular velocity increases, as does angular momentum