Biomechanics (Topic 1B, Scalars, Vectors + Newtons laws of motion)

Scalar quantity (defintition)

Has magnitude (size) but no direction.

Examples of scalar quantities + Unit

Time (seconds)

Length (meters)

Speed (ms-1)

Mass (kg)

Area (m2)

Vector Quantity (defintion)

Has magnitude (size) and acts in a particular direction

Examples of vector quantities + Unit

Force (N)

Weight (N)

Acceleration (ms-2)

Velocity (ms-1→)

Displacement (m→)

Velocity (definition)

The speed of an object in a particular direction

Distance (definition)

The length covered by an object moving from one point to another. (scalar quantity)

Displacement (defintion)

A vector quantity and describes how an object has moved a distance away from its starting point in a given direction.

Speed (definition)

How fast a body moves in relation to time

Speed, distance, Time formulas

Distance = speed x time

Speed = Distance over Time

Time = Distance over speed

Velocity (m/s) Formula

Distance over Time (with Direction →)

Acceleration (definition)

The rate of change of a bodies velocity (vector quantity)

Deceleration (definition)

Opposite of acceleration. it is the rate of decrease in a bodies velocity.

Mass (definition)

The amount of matter a body possesses(Kg).

Weight (definition)

The force exerted on a body by gravity.

Weight (formula)

Mass(kg) x Gravity(m/s)

Motion

The action of changing location or position. Motion is described in terms of displacement, velocity, acceleration, speed and time.

Newtons Laws of motion + Benefit

Forms the basis for principles used in sports movements.

Purpose/Benefits: Athletes and coaches can gain a greater understanding of human biomechanics and how the human bodies motion can be influenced by external factors.

Newtons 1st law of Inertia (e.g. of external forces) (1,2,3 = I,A,C)

An object at rest will remain at rest unless acted on by an external force.

If an object is in motion, it will remain in motion until something stops it.

Gravity

Friction

Weather

Braking on a bike

Newtons 2nd law of Acceleration(1,2,3 = I,A,C)

The velocity of a body is changed only when acted upon by an additional force.

The acceleration or deceleration is produced proportional to and in the same direction of the force. e.g. tackling in rugby can slow down, stop, or reverse in direction depending on the force of the tackle.

Newtons 3rd law of Counterforce (1,2,3 = I,A,C)

The production of any force will create another force opposite and equal to the first force.

e.g. in rowing the oar moves through the water, the force produced created counterforce that pushes the boat in the opposite direction.