Biomechanics
impulse–momentum relationship
define momentum: a measure of the amount of motion possessed by a moving body
mass x velocity
An object can only have momentum if it’s moving.
The greater the momentum the more force that needs to be applied to stop/slow it down
The body with greater momentum is least affected.
define impulse: the application of force over a period of time to change the momentum of an object
force x time
Creates momentum
Changing momentum
To increase momentum: increase force and time component, allows more time for the force to be applied
To decrease momentum: increase time component, reducing the peak force
Stopping momentum
Pratice questions from exams
2025 Q28 B
2023 Q22 a) b)
2020 Q22 c)
2018 Q24 a)
2017 Q30 a)
characteristics of the interacting bodies affecting coefficient of restitution in the application
to sport
Define coefficient of restitution
Measures the elasticity of the collision between an object and a given surface
An object’s COR is measured on 0-1, 1 representing elastic collision (when dropped the ball will rebound to the same height), 0 represents inelastic collision
Identify and describe the three factors that affect it
Equipment and surface,
A High/low COR because the surface/equipment absorb less/more energy resulting in a higher/lower elasticity
temperature
An increase in temperature of the ball results in the higer COR, as energy is kept
Velocity of the collision
Increasing velocity increases the likelihood of the body losing energy due to greater compression of the ball
Apply my knowledge of coefficient of restitution to different sporting contexts
Mention reducing injury, Learning becomes easier,
definition of, application and relationship between the following concepts in sport:
Angular momentumn = moment of interia x angular velocity
Define Momentum of inertia: refers to the resistance of a rotating object to change its state of motion (mass of object x radius of rotation)
Outline how the distribution of mass affects the moment of inertia:
if the mass of an object is distributed close to the axis of rotation the moment of interia is small and the object is easier to rotate -generating a higher angular velocity.
As mass of an object moves further away from the axis of rotation, the moment of interia increases and rotation becomes harder - reducing angular velocity.
Moving the object mass further from the axis rotation, you are increasing its radius of rotation therefore increasing its moment of interia: makes the object harder to control and harder to generate angular velocity
To reduce moment of interia
Angular velocity refers to the rate of change in angular position of a body
A decrease in moment of inertia will meet with an increase in angular velocity and vice versa
Conservation of angular momentum refers to the quantity of angular motion possessed by a rotating body - the motion from a to b doesn’t change
Lesson 6: Bernouli Principle
Practice explaining principle Cause effect performance link, Be able to draw the diagram.
sport examples: F1, Planes, Sailing
Hydrofoil (shape) - creates lift in an upward direction (lift refers to the component of force that acts perpendicular to the direction of flow
Define bernoulis principle (based on shape): Relates to the pressure created from a moving fluid over an object determines the pressure system. whereby fast flowing fluid (air) produces a low pressure area and slow moving (air) fluid produces high pressure area
Explain how the shape and pressure differential of an object is effected by Bernoulli’s principle: When a fluid (like air for example) moves faster, its pressure decreases. When it moves slower, the pressure increases.
e.g: Air flows faster over the top surface of the wing compared to the bottom surface. According to Bernoulli’s Principle, as the velocity of a fluid increases, its pressure decreases. This creates a low-pressure area above the wing and a higher-pressure area below, resulting in lift.
Pratice questions
2022 Q? A) i,ii
2021 Q? a), b)
changes in flight paths in spinning balls - magnus effect in relation to, Top/Back/Side Spin
define magnus effect: Magnus used to describe the effect of rotation on an object’s path as it moves through a fluid eccentric force
analyse the effect top spin can have on the flight path and/or bounce of an object
causes the ball to drop/dip and/or travel shorter in flight
Can be hit with more velocity
analyse the effect back spin can have on the flight path and/or bounce of an object
causes the ball to rise higher in the air and/or travel further e.g sports maximising distance
analyse the effect top spin can have on the flight path and/or bounce of an object
causes the ball to curve to the left or right
Link: curve the ball away from opponents reach or around an obstacle
Define balance, summation of force and optimal projection
Identify factors that affect the above principles
Apply my knowledge to sporting contexts