Topic 1 Chapter 2 - 1.1.4 - 1.1.8 Muscular Skeletal System - Biomechanics Flashcards
What is an Internal Force
When a muscle pulls on it Origin (O) and Insertion (I)
What is a lever?
A lever is a means of applying force at a distance from the source of the force.
What three components make up a lever?
Fulcrum (pivot), effort and load
What is a class 1 lever?
When the fulcrum is in between the effort and load (see-saw lever)
What is an example of a 1st class lever?
The triceps/elbow/forearm lever
The atlas/neck muscles used in a nodding movement
What is a class 2 lever?
When the load is bigger than the effort, and the fulcrum is at one end of the lever (wheelbarrow lever)
What is an example of a 2nd class lever?
The Achilles tendon/calf muscles (gastrocnemius and soleus) and ankle joint
What is a class 3 lever?
When the effort is bigger than the load, and the fulcrum is at one end of the lever
What is an example of a 3rd class lever?
The knee/quadricep/tibia/fibula systems
The elbow/bicep/forearm lever
Which lever class is most commonly found in the body?
3rd class lever
How does the length of a lever affect the load that can be exerted?
The longer the lever the less load can be exerted
How does the length of a lever affect the speed of the load that can be exerted?
The longer the lever the quicker the load can be exerted
How is a mechanical advantage created?
Mechanical Advantage:
Longer effort arm → Less force needed
How is a mechanical disadvantage created?
Mechanical Disadvantage:
Shorter effort arm → More force needed
Name and Explain Newton’s 1st Law of Motion
Law of Inertia:
- An object maintains current velocity
It can be stationary or a constant velocity
- An object / body remains constant until acted on by an external force - gravity, friction, air resistance/drag
Give a sporting example of Newton’s 1st Law
When a sprinter is running at a constant speed
Name and Explain Newton’s 2nd Law of Motion
Law of Acceleration:
- When a net force acts on a body / object which causes acceleration or deceleration
- Bigger the force the greater the impact on body
- Force (N or kg/m^2) = Mass (kg) * Acceleration (m/s^2)
Give a sporting example of Newton’s 2nd Law
When a sprinter is accelerating or decelerating
Name and Explain Newton’s 3rd Law of Motion
Law of Action and Reaction:
- Two bodies act upon each other (action / reaction)
- Forces can be equal or opposite (every action has an equal and opposite reaction)
Give a sporting example of Newton’s 3rd Law
When a sprinter pushes down an backwards on the ground
What is the definition of Centre of Mass?
CofM is the single point (on a body) which represents all the spread out mass of the body OR the balance point of the body
Where must the CofM be to ensure balance of a body?
The CofM must be over the base of support
How is toppling caused?
It is caused by weight acting vertically at the CofM
How can an body achieve equilibrium?
If the body has it’s CofM over the base of support
