YR2 LINEAR MOTION & ANGULAR Flashcards
What is linear motion?
The movement of a body in a straight or curved line, where all the parts move the same
distance in the same direction in the same time
What is linear motion caused by?
Linear motion is caused from a direct force applied to the Centre of a body’s mass (the point at which a body is balanced in all directions (weight acts from this
point)
What is distance?
The total length covered from start to distance in positions (m)
What is displacement?
The shortest straight line distance from start to finish
positions (m)
What is speed?
Equation?
The rate of change is distance (m/s)
Speed = Distance ÷ Time taken
What is velocity?
Equation?
The rate of change is displacement (m/s)
Speed = Displacement ÷ Time taken
What is acceleration?
Equation?
The rate of change in velocity (ms-2)
Acceleration = (Final Velocity –Initial Velocity) ÷ Time taken
Positive Value =
Negative value =
Acceleration
Deceleration
Tips for DISTANCE TIME GRAPHS?
Cannot go down (distance cannot decrease)
Gradient is equal to the speed
Tips for VELOCITY TIME GRAPHS?
Curves show acceleration
Can be positive and negative
Tips for SPEED TIME GRAPHS?
Area under is the distance
Positive gradient acceleration negative deceleration
What is Angular motion?
What is it caused by?
Movement of a body or part of a body in a circular path about an axis of rotation
Angular motion is caused from a eccentric force , a force that is applied outside the
center of mass. An eccentric force is also known as torque, a measure of turning
force applied to a body
What is a sporting example of angular motion?
E.g. a trampolinist body will rotate around her center of mass in a somersault
Name 3 axis of rotation?
Longitudinal
Frontal
Transverse
What is Longitudinal axis:?
Example
Running from head to toe through the center of mass.
A performer rotates around this axis in a flat spin on the
ice during ice dance
What is Transverse axis?
Example
Running from left to right through the center of mass.
A performer rotates around this axis in a somersault
in a vault
What is Frontal axis?
Example
Running from back to front through the center of mass.
A performer rotates around this axis in a cartwheel
What are the three Angular motion descriptors?
Angular Velocity
Moment of inertia
Angular Momentum
What is Angular velocity?
Equation?
Measured in?
The rate of rotation-
Angular velocity = angular displacement/time taken
Measured in Radians (rad)
What is moment of inertia?
Equation?
The resistance of a body to change in its state of angular motion or rotation
Moment of inertia = sum of ( mass x distribution of the mass from the axis of rotation squared)
What two factors affect the moment of inertia?
Mass
Distribution of mass
How does mass affect the moment of inertia?
The higher the mass the higher the moment of inertia (why all gymnasts are small)
The lower the mass the lower the moment of inertia (Rugby props are never small)
How does distribution of mass affect moment of inertia?
The higher the distribution of mass the higher the moment of inertia (why pike flips are harder than
somersaults)
The lower the distribution of mass the lower the moment of inertia
When running -
Drive Phase
Recovery Phase
High or low MOI?
Drive phase:
High MI
Large distribution of mass
Recovery Phase:
Low MI
Low distribution of mass