Biomechanical Movement Flashcards
What is Angular motion?
- Angular rotation refers to rotation
- Rotation is movement around a fixed point/axis
- Can involve the whole body or just an arm or leg
- In a runner, they run in a straight line but have large amounts of rotation in their arms and legs.
What is an eccentric force?
An off-centre force,
When does Angular motion occur?
Angular motion occurs when a force is applied outside the centre of mass.
What is the transverse axis?
- The transverse axis runs from side to side across the body.
- A somersault rotates a body in a transverse axis.
What is the Sagittal axis?
- The Sagittal axis runs from front to back.
- A cartwheel rotates around the sagittal axis.
What is the Longitudinal axis?
- The longitudinal axis runs from top to bottom.
- A multiple spin in ice skating rotates in a longitudinal axis.
What is torque?
Often called the moment, torque is the turning force and causes angular motion to occur.
Torque causes an object to turn about it’s axis of rotation. It is dependent on 2 things:
1) The greater the size of the force, the greater the torque.
2) Application of the same force further away from the axis, will increase torque.
How do you calculate ‘moment of force’?
Moment of force/torque (Nm)= Force (N) X Perpendicular distance from the fulcrum (M)
What are the 2 things ‘moment of force’ can be?
- Resistance arm
- Effort arm
What is the resistance arm?
Shortest perpendicular distance between fulcrum and resistance.
What is the effort arm?
Shortest perpendicular distance between fulcrum and effort.
What is the definition of speed?
Speed can be defined as the rate of change of a position and can be calculated as: speed (m/s)= distance covered (m)/ time taken (s)
What type of quantity is speed?
Scalar quantity
What is velocity?
Velocity refers to how fast a body travels in a certain direction. It is the rate of change of displacement: velocity= displacement (m)/ time (s)
What type of quantity is velocity?
Vector quantity.
What is the equation to calculate average acceleration?
Average acceleration (ms-2)= change in velocity/ time
When is momentum conserved?
Momentum being conserved occurs when a performer or object is in flight. When in flight neither mass nor velocity can be altered. Mass is constant. Velocity can only be altered by external forces (air resistance + gravity).
What is angular velocity?
Refers to the rational speed of an object and the axis about which the object is rotating. It’s a vector, it has direction as it refers to angular displacement covered in a certain time.
What is the equation to find angular velocity?
Angular velocity (rad/s)= Angular displacement (rad)/ time taken (s).
What is angular acceleration and how is it calculated?
The rate of change of angular velocity. Angular acceleration p= (rad/s2)= Change in angular velocity (rad/s)/ time taken (s).
What is Newton’s second law in relation to angular motion?
‘The rate of change of angular momentum (acceleration) a body is proportional to the force (torque) causing it and the change that takes place in the direction which the force (torque) acts.
What is Newton’s third law in relation to angular motion?
‘When a force (torque) is applied by one body to another, the second body will exert an equal and opposite force (torque) on the other body?
What are the 2 factors that the moment of inertia acting on a lever is dependant on?
- The mass of the object.
- How the mass is distributed from the point of rotation. The further the mass from the point of rotation, the bigger the moment of inertia and the harder to stop/start movement.