UNIT 3 EXAM - BIOMECHANICS

Force

Push or pull that produces or changes motion of an object

External forces that affect motion

Gravity, air and water resistance, friction, reaction forces

Friction

Force that occurs when two surfaces are in contact with each other, opposes motion of an object

Torque

The turning effect of the force that has been applied

Angular Velocity

How fast an object or body is spinning

• Increases when radius of rotation decreases (tuck v layout)

• Stays constant unless acted upon by an external torque

• Decrease moment of inertia = greater angular velocity and vise versa

Mass

Amount of matter an object is made up of

Weight

Force exerted on body by gravity

Momentum

Quantity of motion an object has

• Is conserved when objects collide

• Mass x velocity - greater mass = greater momentum

Summation of momentum

Sequential and coordinated movement of each body segment to produce maximum velocity

Angular momentum

Amount of angular motion a body has

Impulse

Change in momentum of an object

Force x Time

Velocity

Describes rate (speed) and direction of motion

Displacement/Time

Projectile Motion

How fast an object is travelling

Distance/Time

Newtons first law

A body will remain at rest or continue in a state of motion unless acted upon by an external force

Newtons Second law - 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

Newtons third law

For every action there is an equal and opposite reaction

Newtons first angular law

Newtons second angular law

Newtons third angular law

Projectile

Any airborne object that is only affected by the forces of gravity an air resistance

• Follows curved path

Vertical impacted by: Gravity (90m/s)

Horizontal impacted by: air resistance

Projectile path impacted by:

• Speed of release

• Angle of release

• Height of release

Height of release greater than 0

Inertia

Tendency of a body to resist a change in motion

• Greater the mass, the greater the inertia

Equilibrium

State of motion at rest or constant velocity, where all forces and torques are balanced

Stability

The body’s ability to resist a change in its current state

• Base of support

• Centre of gravity (higher = less stable)

• Line of gravity

• Mass

• Friction between body and surface contacted

Balance

The ability to maintain and control the equilibrium of the body in different situations

Levers

Axis, resistance, force

Longer levers have higher inertia

Anatomical

Axis (joint)

Resistance (body part of weight being moved)

Force (applied by a muscle)

Mechanical advantage

Measure of efficiency of lever system

3rd class <1 - Large force is required to move small resistance