Biomechanics Flashcards
What is Newton’s First Law of Motion?
Law of Inertia
What is Newton’s Second Law of Motion?
Law of Acceleration
What is Newton’s Third Law of Motion?
Law of Reaction
What is the Law of Inertia?
Where a body continues in a state of rest or uniform velocity unless acted upon by an external or unbalanced force.
e.g. 100m sprinter overcoming force to move out of blocks
What is the Law of Acceleration?
Where a body’s rate of change in momentum is proportional to the size of the force applied and acts in the same direction as the force applied.
e.g. Greater force applied by 100m sprinter to move from blocks = greater the change in momentum
What is the Law of Reaction?
Where for every action force applied to a body, there is an equal and opposite reaction force.
e.g. 100m Sprinter applies force to the blocks and the blocks provide an equal and opposite force
What is the formula for Distance (m)?
Speed (m/s) x Time (s)
What is the formula for Displacement (m)?
Velocity (m/s) x Time (s)
What is the formula for Force (N)?
Mass (kg) x Acceleration (m/s/s)
What is the formula for Weight Force (N)?
Mass (kg) x Acceleration (9.8 m/s/s)
What is the formula for Momentum (kgm/s)?
Mass (kg) x Velocity (m/s)
What is the formula for Acceleration (m/s/s)?
(Final Velocity (m/s) - Initial Velocity (m/s)) / Time (s)
What is a force?
A push or pull that acts on a body
Name the two types of force and how they are generated.
Internal = Skeletal muscle (inside body) External = Weight/Reaction/Friction/Air Resistance (outside body)
What are the 6 effects that force has on the body?
- Create motion
- Accelerate
- Decelerate
- Change direction
- Change shape
- No effect
What can Resultant Force be defined as?
The net sum of all the forces present
What is Weight Force?
Weight which is always present, acting from the centre of mass (origin) directly down to the centre of the Earth (vertical).
What is Reaction Force?
Reaction which is always present, acting from each point of contact (origin) when two bodies are in contact in the opposite direction to weight (vertical).
What is Friction Force?
When two surfaces are in contact and there is motion with the origin being each point of contact and acts in the direction of motion (horizontal).
What is Air Resistance?
Force acting when a body is moving through the air with the origin being the centre of mass and the direction being opposite to that of the motion (horizontal).
Define Centre of Mass.
The point at which a body is balanced in all directions
Define Stability.
The ability of the body to resist motion and remain at rest and the ability of a body to withstand force applied and return to an original position without damage.
What factors affect Stability and what is their impact?
- Mass (Stable = Higher, Unstable = Lower)
- Height of Centre of Mass (Stable = Lower, Unstable = Higher)
- Base of Support (Stable = More, Unstable = Less)
- Line of Gravity (Stable = Inside, Unstable = Outside)
What does FLE stand for when concerning levers?
F - fulcrum
L - load
E - effort
What is the Load Arm?
The distance between the load and the fulcrum
What is the Effort Arm?
The distance between the fulcrum and the effort
What parts of the body do FLE and LA/EA identify as?
Fulcrum = Joints
Load = Limbs/Objects carried
Effort = Muscle
Effort/Load Arm = Bones
What is a 1st Class Lever?
Where the fulcrum is the middle component;
e.g. Elbow when throwing
What is a 2nd Class Lever?
Where the load is the middle component;
e.g. Balls of feet to then raise calves
What is a 3rd Class Lever?
Where the effort is the middle component;
e.g. Bicep Curl
In what class of lever is the Effort Arm longer than the Load Arm?
2nd Class Lever
In what class of lever is the Load Arm longer than the Effort Arm?
3rd Class Lever
Name three types of analysis technology.
- Limb Kinematics
- Force Plates
- Wind Tunnels
What are Limb Kinematics?
Where trackers are placed over a persons body and the simple motions of which a limb can carry out are monitored.
What are Force Plates?
Measuring instruments that measure reaction forces generated by a body moving on them or across them.
What are Wind Tunnels?
Apparatus used for producing an airstream of known velocity past models or people to investigate flow or air resistance.
What are the three types of Linear graphs?
Distance-Time Graphs
Speed-Time Graphs
Velocity-Time Graphs
Define Linear Motion.
The movement of a body along a straight path using one-dimensional motion.
Define Angular Motion.
The movement of a body in a circular path about an axis of rotation as a result of an eccentric force applied outside the body’s centre of mass.
What are the 3 axis of rotations?
- Longitudinal Axis (Head to Toe) (Cartwheel)
- Transverse Axis (Side to Side) (Somersault)
- Frontal Axis (Back to Front) (Pirouette)
What are the 3 descriptors of Angular Motion?
- Angular Velocity
- Moment of Inertia
- Angular Momentum
Define Angular Velocity.
The rate at which something rotates
Define Moment of Inertia.
Resistance to a change in the state of angular motion/rotation
Define Angular Momentum.
The quantity of rotation of a body, which is the product of its moment of inertia and its angular velocity.
What is the formula for Angular Velocity (rad/s)?
Angular Displacement (rad) / Time Taken (s)
What is the formula for Moment of Inertia (kgm²)
Sum of Mass (kg) x Distribution of Mass from axis of rotation (m²)
What is the formula for Angular Momentum (kgm²rad/s)?
Moment of Inertia (kgm²) x Angular Velocity (rad/s)
What is the link between distribution of mass and moment of inertia?
The further the mass from the axis of rotation, the greater the moment of inertia
Once generated, angular momentum is a…
Conserved quantity
What is the Angular analogue of Newton’s Laws?
A version of Newton’s Laws of Motion adapted to angular motion.
What is Newton’s 1st Law of Angular analogue?
Moment of Inertia = A rotating body will continue to rotate about it’s axis of rotation with constant angular momentum unless acted upon by an eccentric force or external torque.
What is Newton’s 2nd Law of Angular analogue?
Angular Velocity = A body’s rate of change in the angular momentum is proportional to the size of the eccentric force or external torque applied and acts in the same direction.
What is Newton’s 3rd Law of Angular analogue?
Angular Momentum = For every torque that is exerted by one body on another body, there is an equal and opposite torque exerted by the second body on the first.
What are the different types of spin?
- Top spin
- Back spin
- Slice
- Hook
