Physics of Motion and Biomechanics

These flashcards cover key concepts related to physics and biomechanics, including momentum, torque, and injury mechanisms.

Linear Momentum

The product of mass (inertia) and velocity, represented as Mo = m × v.

Angular Momentum

The product of moment of inertia and angular velocity, represented as L = I × ω.

Impulse

The ability to change an object's momentum by the product of force exerted over a period of time.

Ground Reaction Force

The force the ground produces back on a user when we walk, run, jump, and move.

Newton’s 2nd Law of Motion

States that the force is equal to mass times acceleration, F = ma.

Right Hand Rule

A method to determine the direction of angular velocity using your hand's position.

Conservation of Momentum

In the absence of external factors, the total momentum of a given system remains constant.

Torque

An off-center force that causes or tends to cause rotation, measured in N×m or lb×ft.

Mechanical Work

The product of the force applied against resistance and the displacement of the resistance, represented as W = F × d.

Mechanical Power

The amount of work performed over a given time period, represented as P = W/Δt.

Moment Arm

The radius of gyration that affects torque; the distance from the fulcrum to the line of action of the force.

Lever System

A biomechanical system composed of a fulcrum, force arm, and resistance arm used in many body movements.

Mechanical Stress

Loading experienced inside a material as expressed per cross-sectional area.

Deformation

A change in shape due to loading on a tissue.

Strain

A measure of the amount of deformation divided by the original length of the material.

Bernoulli’s Principle

Describes the inverse relationship between relative velocity and relative pressure in a flowing fluid.

Magnus Effect

The phenomenon where a spinning ball creates a pressure difference, causing it to curve.

Cushioning (Shock Absorption)

Reduces impact forces during collisions by deforming/changing the shape of materials.

Traumatic Injury

An injury caused by a sudden imposition of stress on tissue, such as fractures or sprains.

Fatigue Injury

An injury that occurs due to the accumulation of microtrauma over time, like stress fractures.

Nitric Oxide Synthase (NOS)

An enzyme that acts as a stress-strain sensor, producing nitric oxide upon mechanical stress.

Fluid Pressure

The ability to produce a force over an area of contact; measured in N/m² or pascals (Pa).

Mechanical Advantage

The effectiveness of a lever system in moving resistance, calculated as DFA/DRA.

Agonist/Antagonist Pairs

Muscle pairs where one muscle acts as the agonist (prime mover) and the other as the antagonist.