B.2.1 sports science

Newton’s Laws of Motion

Newton’s First Law (Inertia)

An object remains at rest or in constant motion unless an external force acts on it.

Newton’s Second Law (Acceleration)

Force equals mass times acceleration (F=ma); acceleration depends on the mass and force applied.

Newton’s Third Law (Action/Reaction)

For every action, there is an equal and opposite reaction.

Section B.2.1 Linear Motion & Forces

Force

A push or pull that changes the state of motion of a body (Measured in Newtons).

Mass

The amount of matter in a body; stays constant regardless of gravity (Measured in kg).

Weight

The force exerted on a mass by gravity (Weight = mass x gravity).

Displacement

The straight-line distance and direction from the start point to the end point.

Distance

The total length of the path traveled by an object, regardless of direction.

Velocity

The rate of change of displacement (Velocity = displacement / time).

Speed

The rate at which an object covers distance (Speed = distance / time).

Acceleration

The rate at which velocity changes over time.

Momentum

The quantity of motion of a moving body (Momentum = mass x velocity).

Impulse

The change in momentum caused by a force applied over time (Impulse = Force x time).

Scalar

A measurement that has size (magnitude) only, such as speed or mass.

Vector

A measurement that has both size (magnitude) and direction, such as velocity or weight.

Section B.2.1 Angular Motion

Axis of Rotation

The imaginary line around which a body or object rotates.

Angular Displacement

The change in the angle of a body as it rotates around an axis.

Angular Velocity

The rate at which a body rotates around an axis (Angular displacement / time).

Angular Acceleration

The rate of change of angular velocity over time.

Moment of Inertia

A body's resistance to change its state of rotation; depends on mass distribution.

Angular Momentum

The amount of rotation of a body (Angular Momentum = Moment of Inertia x Angular Velocity).

Torque (Moment of Force)

The turning effect produced by a force applied away from an axis.

Biomechanics Concepts

Center of Mass

The point at which the mass of a body is evenly distributed in all directions.

Base of Support

The area of the body in contact with the ground or supporting surface.

Line of Gravity

An imaginary vertical line passing through the center of mass to the ground.

Stability

The ability of a body to resist being moved or overturned.

Equilibrium

A state where all acting forces are balanced, resulting in no change in motion.