KEY KNOWLEDGE 3.1.5 BIOMECHANICAL PRINCIPLES FOR …

© Chris Branigan & Edrolo 2017 1

VCE PHYSICAL EDUCATION UNIT 3 AOS 1

Presented by Chris Branigan

Study design dot point:• Biomechanical principles for analysis of human movement including: angular and linear kinetic concepts of human

movement: Newton’s three laws of motion, inertia, mass,force, momentum and impulse– angular and linear kinematic concepts of human movement: distance, displacement, speed, velocity,acceleration and projectile motion (height, angle and speed of release)– equilibrium and human movement: levers (force, axis, resistance and the mechanical advantage ofanatomical levers), stability and balance (centre of gravity, base of support and line of gravity)

BIOMECHANICAL PRINCIPLES FOR ANALYSIS OF MOVEMENT (PART 3)

KEY KNOWLEDGE 3.1.5


Concept Difficulty Concept reference Questions

Newton’s Laws of Motion KK 3.1.5.6

Motion (Linear & Angular) KK 3.1.5.7

What’s in this lesson?


Recap: What is biomechanics?Biomechanics is the science that studies living things from a mechanical perspective. Using the principles of physics associated with movement and forces, biomechanics can help to develop and refine human movement.

Pioneers: The Fosbury Flophttps://www.youtube.com/watch?v=tBmOF6Zsj_o


Theory summaryNewton’s laws of motion are comprised of three laws:• The law of inertia: A body will remain at rest or in uniform motion in a straight line unless acted upon by an

external force.• The law of force and acceleration: A force applied to an object will produce a change in motion (acceleration)

in the direction of the applied force that is directly proportional to the size of the force.• The law of action-reaction: When two objects come in contact with one another, they exert forces that are

equal in size but opposite in direction on each other – for every action there is an equal and opposite reaction.

Lets look at all three laws in action together.

Newton’s Laws of MotionsKK 3.1.5.6

Source: https://www.youtube.com/watch?v=1cfAqc6yNj0


Theory summary• The law of inertia: the angular momentum of a body remains

constant unless acted upon by an external torque.• The law of force and acceleration: a torque applied to an object

will produce a change in angular motion in the direction of the applied torque that is directly proportional to the size of the torque and inversely proportional to the moment of inertia of the object.

• The law of action-reaction: for every torque there is an equal and opposite torque

Angular MotionNewton’s Laws of MotionKK 3.1.5.6

Torque (n.)A rotational force (a push or pull) that makes an object rotate.

Explanation• The amount of angular motion possessed by a body is known as its angular momentum. It is the product of

the moment of inertia and the angular velocity of an object rotating around an axis.• The moment of inertia of a body is the product of the distribution of mass of the object and the axis about

which it rotates:

Moment of Inertia = mass x radius2

Source: https://www.youtube.com/watch?v=AxwdhweBmv8


Theory summary• Conservation of angular momentum• Angular momentum is conserved when the body is in flight.• If the total angular momentum of a body is conserved, and the mass of the body cannot be changed, then

there must be a trade-off between angular velocity and moment of inertia.

Angular Motion (cont’d)Newton’s Laws of MotionKK 3.1.5.6

Torque (n.)A rotational force (a push or pull) that makes an object rotate.

Source: https://www.youtube.com/watch?v=4ysjURAArmg


Theory summaryThere are three types of motion that we will discuss:• Linear motion• Angular motion• Projectile motion

That said, almost all human motion is considered to be general motion, as it is a combination of linear motion and angular motion.

Motion (Linear & Angular)KK 3.1.5.7

Source: https://www.youtube.com/watch?v=1cfAqc6yNj0


Theory summary• Describing the motion can be done my looking at the distance, displacement, speed, velocity and acceleration

of the body.• These characteristics are quantitative which means that they can be calculated.

Explanation• Distance and displacement both measure distance; however, distance measures how far someone has

travelled from beginning to end, while displacement measures how far they have moved from the starting point.

• For example, running a 400m sprint on a 400m Athletics Track gives us a running distance of 400m and a running displacement of 0m.

Examples• In a sporting context, distance, is commonly used in preference to displacement. The fitness staff at an AFL

club will be much more interested in the distance travelled by a player in a game, rather than the player’s displacement.

Linear motionMotion (Linear & Angular)KK 3.1.5.7

Linear Motion (n.)Linear motion is the movement of the body along a straight or curved path.


Theory summary• How quickly an object covering distance is called speed. • How quickly an object is changing position, relative to its starting position, called velocity.

Both are measured in metres per second.

The equation for speed:Speed = distance/time

The equation for velocity:Velocity = displacement/time

It is important to note that velocity is expressed as both the size and direction. For example the ball moved at 30m/s north.This means that velocity has changed if either the size, direction or both change.

Linear motionMotion (Linear & Angular)KK 3.1.5.7

Speed (n.)How quickly an object covers distance.

Velocity (n.)How quickly an object is changing position relative to its starting position.


Multiple choice activityWhich of Newton’s Laws is critical in explaining why athletes run slower on soft sand than they do on the road?

A. Newton’s First Law

B. Newton’s Second Law

C. Newton’s Third Law

D. I don’t know.

(Written by the author)

Newton’s laws of motionKK 3.1.5.6


Multiple choice – ResponseWhich of Newton’s Laws is critical in explaining why athletes run slower on soft sand than they do on the road?

A. Newton’s First Law

B. Newton’s Second Law

C. Newton’s Third Law

D. I don’t know.


Newton’s laws of motionKK 3.1.5.6


Multiple choice activityWhat has Courtino focussed on to ensure that the ball has the maximal amount of right to left curve.

A. Kick the right hand edge of the ball

B. Kick the ball between the right hand edge of the ball and the centre of gravity

C. Kick the ball through the centre of gravity

D. I don’t know.



Source: https://www.youtube.com/watch?v=nSFnIbtHqXM


Multiple choice – ResponseWhat has Courtino focussed on to ensure that the ball has the maximal amount of right to left curve.

A. Kick the right hand edge of the ball

B. Kick the ball between the right hand edge of the ball and the centre of gravity

C. Kick the ball through the centre of gravity

D. I don’t know.



Source: https://www.youtube.com/watch?v=nSFnIbtHqXM


Lesson summaryUNITS 3&4

The principles covered in this lesson are rarely working in isolation. During many sporting actions, several of the biomechanical principles are involved. Being able to identify which principle, or principles, are being used by an athlete and

how applying these principles correctly can improve sporting performance will be the basis of assessment for this topic.

Concept Theory summary

Newton’s Laws of MotionThere are three of these and the laws often form the basis of biomechanics. In most sporting performances there are a combination of all three laws in action.

Motion (Linear & Angular) We looked at linear and angular. There is different terminology used to describe each type of motion, so knowing the terminology and when it is appropriate to use it is critical.


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VCAA exams and related content can be accessed directly at www.vcaa.vic.edu.au

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