biomechanics yr 1

Question 1

centre of mass

Answer 1

the point at which the body is balanced in all directions

Question 2

Fosbury flop technique in relation to COM

Answer 2

-uses j curve to allow greater velocity in approach
-plants outside foot to allow inside foot to lift along with the arms at take off to raise the COM as high as possible
-full extension of the spine too rotate arounds the bar moving the COM outside the body and below the bar
-only one section of body around the bar at one time

-because the COM is below the bar the Fosbury flop requires less force at take off to clear the same heights as earlier techniques

Question 3

4 factors that affect stability

Answer 3

mass of body - the greater the mass of there body the greater its inertia and therefore stability

height of the COM - lower the COM the greater the stability

Base of support - greater the size of the base of support the greater the stability as you can increase surface area or have more points of contact on the floor

line of gravity - an imaginary line which extends from the COM down to the floor, the more central the line is to the base of support the more stability

Question 4

example of runner maximising stability

Answer 4

crouched position gives a low COM
base of support large with 5 points of contact
line of gravity within the base of support and sprinter has a high mass due to muscle mass

Question 5

stability

Answer 5

the ability of a body to resist motion and remain at rest

Question 6

mechanical advantage

Answer 6

second class lever systems where the effort arm is greater than the load arm

Question 7

mechanical disavadntage

Answer 7

third class lever system where the load arm is greater than the effort arm

Question 8

lever systems

Answer 8

co-ordination of our bones and muscles primarily to create human movement

Question 9

biomechanics

Answer 9

the study of human movement and the effect of force and motion on sport performance

Question 10

Newtons 1 law

Answer 10

the body remains at rest or uniformed velocity until acted on by and external or unbalanced force

Question 11

inertia

Answer 11

the resistance of a body top change its state of motion whether at rest or moving

Question 12

newtons second law

Answer 12

a body rate of change in momentum is proportional to the size of the force applied and acts in the same direction as the force applied

Question 12

newtons second law

Answer 12

a body rate of change in momentum is proportional to the size of the force applied and acts in the same direction as the force applied

Question 13

momentum

Answer 13

the quantity of motion possessed by a moving body

Question 14

newton 3 law

Answer 14

for every action force applied to the body there is an equal and opposite reaction force

Question 15

velocity def and eq

Answer 15

the rate of change in displacement

displacement / time taken

Question 16

momentum eq

Answer 16

mass x velocity

Question 17

acceleration def and eq

Answer 17

rate of change in velocity

final velocity - initial velocity / time taken

Question 18

force

Answer 18

push or pull that alters the state of motion on a body

f=ma

Question 19

5 effects of force

Answer 19

create motion
accelerate a body
decelerate a body
change the direction of the body
change the shape of a body

Question 20

weight def and eq

Answer 20

the gravitational pull the earth exerts on the body

mass x acceleration due to gravity

Question 21

2 vertical forces

Answer 21

weight and reaction

Question 22

4 factors that affect friction

Answer 22

roughness of the ground surface - by increasing roughness friction is increased

roughness for contact surface - by increased roughness of contact surface friction increases

temperature - increased temp of ground leads to more contact surface friction

size of normal reaction - increased normal reaction force leads to increased friction e.g shot put have high mass therefore reaction force is high allowing for greater friction in the turning circle

Question 23

4 factors that affect AR

Answer 23

velocity- by increasing velocity AR increases

Shape- more aerodynamic shape the less AR

Frontal CSA- by decreasing the Frontal cross sectional area Ar decreases

smoothness of surface- increasing the smoothness of the surface air resistance decreases

Question 24

limb kinematics

Answer 24

the study of movement in relation to time and space

3D analysis records an athlete performing a sporting action and allows joint and limb efficiency to be evaluated

Question 25

pros and cons of limb kinematics

Answer 25

+immediate data
+highly accurate
+used by coaches to adjust technique
- dependant on correct placement of body markers
-does not cater for individual differences
- expensive
-limited to lab conditions

Question 26

force plates

Answer 26

measures ground reaction force
assess the size and direction force acting on the athlete

Used for gait analysis

rectangular plate with built in force transducers usually sunk into the ground to become part of the floor and electrical output proportional to the force applied is displayed

Question 27

pros and cons of force plates

Answer 27

+immediate
+accurate
+reliable
-expensive
-specialist
-lab conditions

Question 28

Wind tunnels

Answer 28

objects are tested for aerodynamic efficiency
Object is placed inside the wind tunnel with instruments to measure the forces produced by the air against the surface

Question 29

pros and cons of wind tunnels

Answer 29

+ tight control over environmental variables
+ accurate measurements of AR
+ quick results
- specialised facilities
-expensive
-complex analysis needed from professionals