VCE Unit 3 Biomechanics

force

the push or pull acting on an object. F= m x a

friction

Force that acts in the opposite direction to motion when 2 surfaces are in contact with one another.

inertia

Tendency of a body to resist change in its state of motion

momentum

measure of the amount of motion an object has and its resistance to change

momentum=

mass (kg)x velocity (m/s)

conservation of momentum

whenever two bodies collide, the combined momentum of the two bodies is conserved

Summation of Momentum

sequential movement of each body segment to generate more momentum

angular momentum

Quantity of angular motion of an object

angular momentum=

moment of inertia x angular velocity

Moment of inertia=

mass x radius

impulse

the change of momentum of an object when the object is acted upon by a force for over time

impulse=

force x time

newtons first law-

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

newtons second law-

Acceleration of an object depends on its mass and on the force applied to it

torque

a twisting force

newtons third law-

For every action there is an equal and opposite reaction

linear motion

Movement of a body along a straight line or curved path where all body parts move in the same direction at the same speed.

distance

The path travelled by a body from point A to B

displacement

A change in the position of a body in relation to its starting position

speed

time taken to cover distance- speed= distance/ time (m/s)

velocity

The time taken change position- velocity= displacement/ time (m/s)

acceleration

A change in velocity in a given period of time- can be speeding up/ down or remaining constant

acceleration=

Change in velocity / Change in time (m/s)

angular motion

Rotation around a central axis or fixed point, measured in degrees

angular distance

The distance an object travels (measured in degrees) around an axis

angular displacement

difference between the initial and final position of an object that has travelled around an axis (measured in degrees)

projectile motion

Horizontal component: relates to the horizontal distance covered

Vertical component: relates to the height reached

Factors influencing path of a projectile

angle of release, speed of release, height of release

Equilibrium

When all forces and torques are balanced

stability

The ability of a body to resist change in its current state of equilibrium

base of support

The area of an object that is in contact with the surface supporting it

Centre of gravity

The central point of an object, about which all of its weight is evenly distributed and balanced

Line of Gravity

An imaginary line that passes through the centre of gravity in the direction that gravity acts

lever

A simple machine consisting of a rigid bar that can be made to rotate around an axis.

Have an axis (fulcrum), resistance (load) and a force (effort).

1st class lever

FAR

2nd class levers

ARF

3rd class levers

AFR