Transcript 3 rd CLASS - MissCalnan

Biomechanics
 The
study of forces and their effects on the
human body
 Sir
Isaac Newton developed three basic laws
that explain the relationship between motion
and force
A
push, a pull or a twist
 Force
= Mass x Acceleration
 LAW

“A body continues in its state of rest or uniform
motion unless an unbalanced force acts upon it“
 So

OF INERTIA
what does this mean?
A body will remain at rest or will continue
moving (in the same direction) until another
force acts on it
 Inertia

is…
a body’s tendency to remain at rest or in motion.
The more mass an object has, the larger its
inertia is. Therefore is more reluctant to change
its state of motion.
 Who
has more inertia
in this image?
 This
soccer ball will remain at rest until a
force acts on it…

e.g. strong winds, or someone kicking it
 LAW

‘The acceleration of an object is directly proportional
to the force causing it, is in the same direction as the
force, and is inversely proportional to the mass of the
object’
 This

OF ACCELERATION
means…
When a force is applied to an object it will move in the
direction the force was applied, and, depending on the
size of the force and the size of the object, the object
will accelerate accordingly
 Class
experiment…
A
smaller object will move faster than a
larger object.
 A greater force will move an object faster
than a smaller force
Force = Mass x acceleration
 THE
LAW OF REACTION

‘Whenever a force is applied there is an equal
and opposite reaction’

e.g. Jumping
If a person exerts a force onto
the ground in order to push off, the
ground will exert an equal and opposite
force on the person, pushing them up

into the air
Downward
Upward
 HANDBALL


EXAMPLE
In your groups, choose ONE of Newton’s Laws
Describe how you can use this law to your
advantage in Handball


Levers allow you to apply force and speed more easily.
Consist of 5 parts - Fulcrum (pivot point), Force, Force
arm, Resistance and a Resistance Arm
FORCE
Resistance
Fulcrum
FORCE ARM
Resistance ARM
 Allow
body
 e.g.
force to be applied from Outside the
Are inside the human body.
 Most important Levers
 These levers are made up of a:
 Joint = Fulcrum
 Bones = Lever arms
 Muscles = Force

Load = resistance
 Effort = force

 Levers



can be classed into 3 types:
1st Class
2nd Class
3rd Class – Most levers in human body are 3rd class
 In
a 1st Class Lever, the Fulcrum sits between
the load (resistance) and force applied (effort)
 e.g.
See-saw
 In
a 2nd Class Lever, the Load (resistance) sits
between the fulcrum and the force applied.

e.g. Wheel Barrow
 In
a 3rd class lever, the force applied sits
between the Fulcrum and the load (resistance)
 Third class levers allow more speed to be
produced because resistance arm is longer
than force arm
 e.g. Bicep curl

To Manipulate the Lever length the resistance
arm needs to be altered (via bending or
straightening the joint)

Longer levers result in greater speed at the end
of the lever arms – this is beneficial for throwing
and striking objects (e.g. throwing a handball).

Short levers result in fast and strong movements
to occur– this is beneficial for moving body parts
quickly and applying strength for pushing, pulling
and lifting objects.
1. What class of lever are most of the limbs in
human body?
 2. Force = _______ x ________
 3. Newton’s 1st law is the law of _______
 4. Newton’s 2nd law of reaction means… ?
 5. What type of joint is the elbow joint? And
what muscle causes elbow flexion

1. What class of lever are most of the limbs in
human body? 3rd CLASS
 2. Force = MASS x ACCELERATION
 3. Newton’s 1st law is the law of INERTIA
 4. Give an example of Newton’s 2nd law?
 BOUNCING A BALL, JUMPING
 5. What type of joint is the elbow joint? And
what muscle causes elbow flexion
 HINGE JOINT, BICEP

‘the sum of all forces generated by each body
part’
 Force summation allows maximum force to be
produced
 For maximum force production:

1.
2.
3.
4.
The force from all different body segments needs to
be added together
Use large muscles  then smaller muscles
You need to sequence timing of body segments
The more body segments that are involved in the
movement, the more possible force that can be
produced

Throwing example:
Large Force
Force Produced
Hand
Small Force
Shoulder/arm
Hand
Trunk
Shoulder/arm
Time
Hip/thigh/leg

As soon as an object is thrown it becomes a
projectile.

The distance an object travels is dependant on
many factors, including:
Speed of release
 Angle of release
 Height of release


A projectiles speed of release is determined by:
Force summation
 Levers


The greater the speed of release = the greater
distance traveled.

When aiming for maximum distance, the optimal
angle of release is 45 degrees
Different activities require a different angle of
release…
 e.g. Hand ball shot at goal (-45 degrees)


e.g. Throwing a shot put (45 degrees)

– High release to get greater distance

By increasing the height of release, the object
will travel a greater distance

e.g.

Complete the revision worksheet