motion

Question 1

What is the definition of linear motion?

Answer 1

Linear motion is movement in a straight line or curved path where all body parts move in the same direction and at the same speed.
It can be rectilinear (straight) or curvilinear (curved), and is measured using distance, displacement, speed, velocity, and acceleration.

Question 2

What is the difference between distance and displacement?

Answer 2

Distance is the total path travelled, regardless of direction (a scalar quantity).

Displacement is the shortest straight-line measurement from the starting point to the finishing point, including direction (a vector quantity).

Question 3

What are the formulas for acceleration, displacement, and velocity in linear motion?

Answer 3

Velocity (v) = displacement (s) ÷ time (t)

Acceleration (a) = change in velocity ÷ time

Displacement (s) = ut + ½at²
u = initial velocity
v = final velocity
a = acceleration
t = time
s = displacement

Question 4

What is the definition of angular motion

Answer 4

Angular motion is movement around an axis where body parts follow a circular path.
Occurs when a force (torque) is applied outside the centre of mass, causing rotation.

Question 5

What is angular momentum?

Answer 5

Angular momentum is the quantity of rotational motion an object has.
It depends on moment of inertia and angular velocity, calculated by:
Angular momentum = moment of inertia × angular velocity

Moment of inertia: How mass is distributed around the axis.

Angular velocity: The speed of rotation.

The greater the moment of inertia or angular velocity, the greater the angular momentum.

Question 6

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

Answer 6

A:
Angular momentum = Moment of inertia × Angular velocity

If mass is closer to the axis (e.g., in a tucked position), moment of inertia ↓, angular velocity ↑

If mass is spread further from the axis (e.g., in a layout position), moment of inertia ↑, angular velocity ↓

Angular momentum remains constant in flight (conservation of angular momentum).

Question 7

What are the formulas for angular acceleration, displacement, and velocity?

Answer 7

Angular velocity (ω) = angular displacement (θ) ÷ time (t)
Angular acceleration (α) = change in angular velocity ÷ time
Angular displacement (θ) is measured in radians or degrees, and is the angle an object rotates through.