Flashcards in Biomechanics Years 1 & 2 Deck (85)
Define Newton's 1st Law
A body continues in a state of rest or moving with constant velocity in a straight line, unless acted upon by an external force.
Define Newton's 2nd Law
When a force acts on an object, the rate of change of momentum experienced by the object is proportional to the size of the force and takes place in the direction in which the force acts.
Define Newton's 3rd Law
For every action, there is an equal and opposite reaction.
The rate of change in displacement
How do you calculate velocity?
Velocity (m/s) = Displacement (m)/Time taken (s)
The quantity of motion possessed by a moving body
How do you calculate momentum?
Momentum (kgm/s) = mass (kg) x velocity (m/s)
The rate of change of velocity
How do you calculate acceleration?
Acceleration (m/s/s) = Final velocity - initial velocity / time taken
How do you define centre of mass?
The point where the mass of the body tends to be concentrated and balanced in all directions
What factors affect stability?
- The mass of the body
- Size of the base of support
- Height of the centre of mass
- No. of points in contact with the surface
- Proximity of the line of gravity to the centre of the base of support
What is the line of gravity?
An imaginary line which extends from the centre of mass directly to the ground
How can you increase stability?
- Increase mass of the body/ object
- Increase the size of the base of support
- Lower of the centre of mass
- Increase the number of points in contact with the surface
- Bring the line of gravity inside the base of support
How do you calculate force?
Force (N) = Mass x Acceleration (F=Ma)
A push or pull that alters the state of motion of a body. (N)
What is Net Force?
The overall force acting on a body when all individual
forces have been considered
What is a balanced force?
Balanced Forces: When two or more forces acting on a body are equal in size but opposite in direction. – Net Force is ZERO.
What is an unbalanced force?
When force acting in one direction on a body is greater in size than force acting in the opposite direction. – Resulting in Net Force
Name two vertical forces?
Weight & Reaction Force
Name two horizontal forces?
Friction & Air Resistance
The force that opposes the motion of two surfaces in contact. (N)
Identify 4 factors that impact upon friction
Roughness or smoothness of footwear or object in contact with the ground.
Roughness or smoothness of the ground or court.
Size of the down force
Temperature of Surface
Identify 4 factors that impact upon air resistance
- Shape of object
- Speed/velocity of release
- Frontal cross sectional area
- Smoothness of surface
What are the 3 components of a lever?
Fulcrum, Effort, Load
What is the fulcrum?
Fixed point of rotation about which the lever moves.
What is the load?
The resistance or weight to be moved. The weight of a human body part to be moved is the load.
What is the effort?
The force being applied that causes the lever to move. The agonist muscle in the human body.
What is the load arm?
The perpendicular distance from the fulcrum to the load.
What is the effort arm?
The perpendicular distance from the fulcrum to the effort.