Biomechanics Principles Flashcards
How many types of motion are there ?
3
List all types of motion.
Linear motion
Angular motion
General motion
Define linear motion.
This occur when all parts of a body move in the same direction, at the same speed, along a straight or curved line
Define angular motion
Occur when a body or body part of a body moves in a circular path around a fixed point(axis of rotation)
Define general motion
The combination of linear and angular motion( the most common type of motion in sport)
Give a sporting example of linear motion
A sprinter running 100m in a straight line
Give a sporting example of a angular motion
A footballer kicking a ball where the leg rotates around the hip
Give a sporting example of general motion
A cyclist moving forward(linear motion) while their legs rotates around around the pedals(angular motion)
How many laws of motion are there ?
3
Who created the law of motion ?
Sir Issac newton
List all the names for the law(s) of motion
1st- law of intertia
2nd- law of acceleration
3rd- law of action and reaction
What is the law of inertia(1st law)
A body remains at rest or in uniform motion unless acted upon by an external force.”
This means an object will stay still or keep moving at the same speed and direction unless something changes it.
Define inertia
Inertia is the tendency of a body to resist a change in its state of motion. An object will remain at rest or continue moving at a constant velocity unless acted upon by an external force.
What is the law of acceleration(2nd)
The acceleration of a body is directly proportional to the force applied and inversely proportional to its mass.
The greater the force applied to an object, the greater its acceleration, but heavier objects require more force to accelerate.
What is the equation for Newton’s second law ?
FORCE(F)= MASS(M) X ACCELERATION(A)
F=ma
What is the law of action and reaction(3rd)
“For every action, there is an equal and opposite reaction.”
When a force is applied to an object, the object applies an equal force in the opposite direction.
Give a sporting example of the Newton’s first law.
A winger will continue to run at a constant velocity in a straight line to cross the ball unless tackled by an external force e.g defender
Give a sporting example of newtons 2nd law.
sprinter applies more force to the ground to increase their acceleration at the start of a race.
Give a sporting example for Newton’s third law.
A swimmer pushes against the wall during a tumble turn, and the wall pushes back, propelling them forward.
Define “force”
A force is a push or pull that alters or tends to alter the state of motion of a body
How many ways can force impact the body
4 different ways to
What are the ways in which a force can cause a body to change?
Change direction- lateral/opposite movement to return a tennis shot
Accelerate- a sprint start, pushing off from the blocks
decelerate- slowing down at the bottom of a ski slope
Changing objects shape- jumping on a trampolines or pressing on a spring
What are the two types of forces ?
Internal forces
external forces
How many types of external forces are there ?
5
List all types of external forces.
Gravity
Friction
Air resistance
Water resistance
Reaction force( ground reaction force)
Elastic forces
Define momentum
Quantity of a motion- the product of mass and velocity
Define Velocity
The speed at which something is moving in a given direction
Define impulse
The product of force and the time taken to apply force
How do you calculate impulse
Force x time
How do you calculate momentum ?
Mass x velocity
How do you calculate velocity ?
Displacement ÷ time
What is
What is net impulse?
Net impulse is the overall change in momentum of an object. It takes into account both positive and negative impulse
How do you Calculate net impulse ?
Total negative impulse - total positive impulse
How many types of impulse is there ?
3
List all types of impulse
Positive
Neutral
Negative
When does positive impulse occur ?
This occurs when a force is applied in the same direction as the motion of an objects increasing its velocity
E,g a sprinter pushing out the blocks applies a forwards force
When does a negative impulse occur ?
This occurs when force applied in the opposite direction to the motion of an object- decreasing its velocity, slowing it down
For example- a long jumper landings in the sand Experinces a braking force from the ground(acting oppositely) reducing their momentum
What are the 3 ways a performer can increase impulse
1 increasing the force applied- applying a greater force results in a larger change in momentum
2 increasing the time the force is applied- extending the duration over which force is applied also increase impulse
- Combining both force and time- the most effective way to increase impulse is to apply a greater force for a longer time.
How does impulse change momentum
The larger the force or the longer it acts, the more momentum changes
Define stability
The ability of a body to return to a equilibrium after being displaced
Define centre of mass
The point at which the body is balanced in all directions
What is the line of gravity
An imaginary line which passes vertically from the centre of gravity to the ground below an object.
How does a wider base of support help an athlete ?
A wider base of support means an athlete can keep their centre of mass over the base of the support much more easier.
How do you calculate balance ?
CENTRE OF GRAVITY over BASE OF SUPPORT
How many types of equilibrium is there ?
3
List all types of equilibrium
Stable
Unstable
Neutral
List all factors affecting stability
Mass of an object
Size of base of support
Number of points of contact
Height of centre of mass
List the 3 components that levers consist off
Fulcrum
Effort
Load
What is the rhyme that helps with remembering levers
1 2 3
F L E
Define the fulcrum
the fixed point or pivot- the point at which a lever rotates around
Define effort(levers)
point where the force/effort is applied (provided by muscle contraction)
Define load
point where the weight/ resistance is coming from(e.g physical object like a dumbbell or basketball)
Relate the fulcrum and load to the human body
Bones act as levers
Joints act as fulcrums
Effort is provided by the muscles
What are the main functions of levers
Increase speed and range of motion
Generate maximal force against a given load/ resistance
Explain where the fulcrum is located in first class lever systems
The fulcrum is in the middle and the effort and load are applied at other ends-
Picture it like a sea saw
The load and effort are interchangeable in the first class lever system(doesn’t matter which side they are on)
Give an example of a first class lever
Elbow extension
Where is the load, effort and fulcrum located for second class lever system ?
Load is in the middle
Fulcrum is on the left
Effort is on the right
Where is the only second class lever located ?
The ankle joint
What is a mechanical advantage
This is where the body can lift heavy loads with little effort, however has a small range of movement and is very slow.
What is a mechanical disadvantage ?
A mechanical disadvantage is being able to have a large range of movement but not able to lift heavy loads, this means that the athlete is able to move at fast speeds.
