Biomechanical Principles and Levers (Paper 2) Flashcards
What does a lever consist of
Fulcrum
Load
Effort
What represents the levers
Bones
What represents joints
Fulcrum
What represents the effort
The muscle
What represents the load
The weight of body part being moved/resistance
What are the three types of levers
First class lever
Second class lever
Third class lever
What does each classification of the levers depend on
The position of the fulcrum, load and effort in relation to each other
What is located on the centre of a first class lever
The fulcrum
What are the two examples of first class levers in the body
Movement of head and neck during flexion and extension
Extension of the elbow
What is located in the middle of a second class lever
The load
Give an example of a second class lever
Plantar flexion of the ankle
What is located in the middle of a third class lever
The effort
Give examples of third class levers in the body
Hip, knee and elbow flexion
(Most levers in the body are third class)
What is the effort arm
The length of the line between where the fulcrum and effort are labelled
What is the load arm
The length of the line between where the fulcrum and the load are labelled
What is a mechanical disadvanatge
-When the load arm of a lever is longer than the effort arm
-the lever system cannot move as heavy a load but can do it faster
-large range of movement
What is mechanical advantage
-When the effort arm is longer than the load arm
-means that the lever system can move a large load over a short distance and requires little force
-Small range of movement
-difficult to generate speed and distance
What is linear motion
Motion in a straight or curved line, with all body parts moving the same distance at the same speed in the same direction
Give an example of linear motion
- 100m athlete will travel with linear motion in a straight line during their race
- 200m athlete will travel with linear motion in a curved line when running the bend
What is inertia
The resistance an object has to a change in its state of motion
What is Newton’s first law of inertia
A force is required to change the state of motion of an object
What is Newton’s second law of acceleration
The magnitude (size) and direction of the force determines the magnitude and direction of the acceleration on an object
What is Newton’s third law of motion
For every action (force) there is an equal opposite reaction (force)
Give a sporting example of Newton’s first law
In the high jump, the athlete runs horizontally towards the bar and then changes their state of motion at take-off when they travel vertically to try and clear the bar
Give a sporting example of Newton’s second law of acceleration
To provide the acceleration at the start of a sprint race an athlete will have to apply a large force internally with their gluteals, quadriceps and gastrocnemius as they drive forward
Give a sporting example of Newton’s third law of motion
At the start of a sprint race the athlete pushes back in the blocks as hard as possible and the blocks push forward on the athlete and provides forward acceleration on the athlete
What is ground reaction force
The equal and opposite force exerted on a performer who applies a muscular force on the ground
What is a scalar quantity
When measurements are described in terms of just their size or magnitude
Give examples of scalar quantities
Speed, distance, mass, temperature
What is speed
The rate of change of position and can be calculated by speed = distance/time
What is distance
The length of the path a body follows when moving from one position to another
What is the centre of mass
- point of balance
- due to the irregular shape of human and it’s constant motion it is hard to identify this point
- e.g. raising your arm in the air raises the centre of mass to keep the body balance
- COM is usually in between the hip region when standing
What is the line of gravity
This is the line extending vertically downwards from the centre of mass and should be central over the base of support to increase stability
What factors affect your stability
- height of the centre of mass
- position of the line of gravity
- area of the support base
- Mass of the performer
What does the area of support base refer to
The amount of contact points of the person
How does lowering you centre of mass affect stability
It increases stability. A low stance makes it harder for an opponent to push you over
What is the mechanical advantage of a second class lever
- can generate much larger forces
What is the mechanical disadvantage of second class levers
- slow
- limited range of movement
What is the mechanical advantage of a first and third class lever
- large range of movement
- any resistance can be quickly moved
What is the mechanical disadvantage of first and third class levers
Cannot apply much force to move an object
what does a vector quantity refer to
when measurements are described in terms of their size and direction
give examples of scalar quantities
weight
momentum
dispalcement
how are vectors represented
by arrows, the length of which shows the magnitude
how is direction shown
by a line of application
point of application
and an arrow head
what is mass
- the scalar quantity of matter the body possesses
- measured in kg
what is weight
- the gravitational force exerted on an object (vector)
- measured in newtons
what is distance
measured in metres and is the path a body takes as it moves from the starting to the finishing position
what is displacement
measured in metres and is the shortest route in a straight line between the starting and finishing point
what is speed
- a measurement in m/s of the body movement per unit of time with no reference to direction
what is velocity
measured in m/s and is the rate of change of displacement
how do you calculate speed
speed(m/s) = distance(m) / time (s)
how is velocity calculated
velocity (m/s) = displacement (m) / time (s)
what is happening when a distance time graph shows a straight horizontal line
the performer/object is stationary
what is happening when a distance time graph shows a straight diagonal line
the performer is moving at a constant speed
what is happening when a distance time graph shows a line that is curved and gradually gets steeper
the performer is accelerating
what is happening when a distance time graph shows a steep curve and starts to becomes levelled off
the performer is decelerating
what does a distance time graph look like
distance on the y axis time on the x axis and then a line to represent the information
what does a constant velocity look like on a velocity time graph
a straight horizontal line
what does an accelerating velocity look like on a distance time graph
the gradient of the line gets steeper
what does a decelerating velocity look like on a distance time graph
a decreasing gradient
what happens when the line in the velocity time graph is above the x axis but then goes below the axis and returns to the x axis
this means there has been a change in direction
what is acceleration
the rate of change of velocity measured in m/s2
how is acceleration calculated
acceleration (m/s2) = change in velocity (m/s) / time (s)
how docalculate change in velocity
final velocity - initial velocity
what is momentum
the product of mass and velocity of an object
how do you calculate momentum
momentum (kg/s) = mass (kg) x velocity (m/s)