Levers + Linear And Amguoar Motion Flashcards
What is a first class lever and example
Fulcrum is in the middle between effort and load
E.g throw in, extension at the elbow
What is a second class lever and example
The load lies between the fulcrum and the effort
E.g calf raises, plantar flexion at the ankle
What is a third class lever system and example
Effort lies between the fulcrum and the load
Everything else apart from throw in and calf raises
What is a mechanical advantage
Where the effort arm is longer than the load arm
What is Mechanical disadvantage
Where the load arm is longer than the effort arm
What is the mechanical advantage at a second class lever
Effort arm is always longer than the load arm
Can generate much larger forces
Has to lift the whole body weight
Can lift large loads over small distances
However difficult to generate speed
Mechanical disadvantage at third class lever
Load arm is always longer than the effort arm
Cannot apply much force to move an object
Large range of movement
Can’t move heavy loads
But can do it faster
What is conservation of momentum
Momentum can also be conserved.
This occurs when a performer or object is in flight. When in flight neither mass nor velocity can be altered.
Mass is constant (unchanged).
Velocity can only be altered by external forces Such as gravity and air resistance.
What does angular motion refer to
Angular motion is movement of a body in a circular path around an axis of rotation
It refers to rotation.
ST FS TL
Angular motion can involve the whole body Or just an arm or leg
When does angular motion occur
Angular motion occurs when a force is applied
outside the centre of mass.
An off-centre force is referred to as an eccentric force.
What’s Newton’s first law of angular motion
Every body continues in it’s state of rest or will turn about its axis of rotation unless changed that state by an external force (torque) acting upon it
What is moment if inertia
Moment of inertia is the resistance of a body to change it’s state of angular motion or rotation
What is factors affecting moment of inertia
Mass - greater mass = greater moment of inertia
Distribution of mass from axis - Further distribution of mass from axis = greater MI
closer = smaller MI
What is moment if inertia
Moment of inertia is the resistance of a body to change it’s state of angular motion or rotation
What is the relationship between moment of inertia and angular velocity
If moment of inertia is low angular velocity is high
If moment of inertia is high angular velocity is low
