More More Biomechanical Biomechanical

TermsTerms

InertiaInertia

Inertia is the term used to describe a body's Inertia is the term used to describe a body's resistance to a change in its state of motionresistance to a change in its state of motion

Think of it as an objects resistance to Think of it as an objects resistance to beginning movementbeginning movement

The heavier the object, the greater its inertia The heavier the object, the greater its inertia and therefore the greater the force required and therefore the greater the force required to move it or change its state of motionto move it or change its state of motion

Activity 1Activity 1In pairs, chest-pass the basketball and medicine ball over three distances (1m. 3m, 5m)

1)Which ball has the greater inertia?2)Which ball is easier to throw over longer distances? Why?3)Note which ball is more difficult to catch or stop (this will be referred to again when discussing momentum)

Activity 2Activity 2

Write down 5 sporting examples of InertiaWrite down 5 sporting examples of Inertia

1.1. A stationary soccer ball resting on the A stationary soccer ball resting on the pitchpitch

MomentumMomentum

The momentum of an object is equal to its The momentum of an object is equal to its mass or weight X by its velocitymass or weight X by its velocity

Momentum – Mass X VelocityMomentum – Mass X Velocity

Therefore, an object can only have Therefore, an object can only have momentum if it is moving. The greater its momentum if it is moving. The greater its momentum, the further it may travel and momentum, the further it may travel and the harder it is to stop or slow the objectthe harder it is to stop or slow the object

Activity 3Activity 3

In the above picture, let's say that the mass is 2.0 kg and that the velocity is 4.0 m/s. That is:m = 2.0 kgv = 4.0 m/s

Using the formula work out the objects momentum and express it in kg-m/s

Some MoreSome More

m = 4.36kgm = 4.36kg

V = 15 m/sV = 15 m/s

==

M= 15.47kgM= 15.47kg

V = 35m/sV = 35m/s

==

Activity 4Activity 4

Explain why the principal of momentum is Explain why the principal of momentum is important in sports and sports important in sports and sports competition competition

ImpulseImpulse The concept of impulse is best described by The concept of impulse is best described by

the following formulathe following formula

Impulse= Force X TimeImpulse= Force X Time

In this equation force equals the objects mass In this equation force equals the objects mass X by its acceleration and time equals the X by its acceleration and time equals the length of time for which the force is applied length of time for which the force is applied to the objectto the object

The longer a force can be applied and the The longer a force can be applied and the greater the force applied, the greater the greater the force applied, the greater the objects impulseobjects impulse

Types of MotionTypes of Motion

3 basic forms of Motion3 basic forms of Motion

• Linear

• Angular

• General

Linear MotionLinear Motion

LinearLinear:: ALLALL parts of parts of the body move through the body move through the same distance, in the same distance, in the same direction, in the same direction, in the same timethe same time

List 3 other examples List 3 other examples of Linear Motionof Linear Motion

Angular MotionAngular Motion AngularAngular (rotation): (rotation): The The

body moves in a circular body moves in a circular path around an axis of path around an axis of rotation so rotation so ALLALL parts of the parts of the body move through the body move through the same anglesame angle, in the , in the same same directiondirection, in the , in the same timesame time

List 3 Examples of List 3 Examples of Angular MotionAngular Motion

General MotionGeneral Motion

GeneralGeneral: : Combination of linear and Combination of linear and angular, and is the most common in angular, and is the most common in human movementhuman movement

Sport/Activity Linear Angular General

100m sprint

Tobogganing down a hill

Teeing off at golf

The shoulder in a cricket bowling actionCycling

Going down a slide

An ice skater spinning