biomechanics

Question 1

what does newtons first law of motion state

Answer 1

an object whether at rest of in motion, will continue in that state unless it is acted upon by a force strong enough to change its state or motion

Question 2

what is an example of newtons first law of motion

Answer 2

A soccer ball wont move from its position unless a force acts upon it (the ball is kicked.)

Question 3

what does newtons second law of motion state

Answer 3

the acceleration of an object is directly proportionate to the amount of force applied and takes place in direction in which the force is applied

Question 4

what is an example of newtons second law

Answer 4

a netball will accelerate faster than a medicine ball (weighted ball) when thrown because it is lighter.

Question 5

what does newtons third law of motion state

Answer 5

for every action there is an equal and opposite reaction.

Question 6

what is an example of newtons third law

Answer 6

when you jump, you legs apply force to the ground, and the ground applies an equal and opposite reaction force that propels you into the air.

Question 7

what is linear motion

Answer 7

linear motion is a one dimensional motion that travels a straight line. it occurs when all parts of object travels over the distance at the same time.

Question 8

what is angular motion

Answer 8

angular motion is also known as rotary motion, it is evident when the body or an object turns around an axis of rotation. an example of this can be doing a somersault, a gymnast completing a bar routine or tumbling in a floor routine.

Question 9

what is general motion

Answer 9

general motion is a mix of linear motion and angular motion. for example for a cyclist, as its arms are involved in linear motion, and its legs are involved in the angular motion (turning of the wheels)

Question 10

what are the functions of levers

Question 11

what is the first class lever

Question 12

what is the second class lever

Question 13

what is the third class lever

Question 14

what are the 3 points that make up a lever

Question 15

what is isometric force

Answer 15

isometric force is when a force is created but no movement is created. an example of this is calf stretches against a wall. another example of this is holding a plank

Question 16

what is isotonic force

Answer 16

isotonic force is large enough to change the state of motion of an object (kicking a ball)

Question 17

what is submaximal force

Answer 17

sub-maximal force is a performer that does not utilise all the force available to complete a task (throwing a tennis ball to someone 1m away)

Question 18

what is maximal force

Answer 18

maximal force is achieved by a combination of perfect timing, maximal muscle contraction and excellent technique (throwing a ball from the outfield)

Question 19

define the term force

Answer 19

any pushing or pulling activity which alters the motion of a body

Question 20

what are examples of objects that are receivers of force in human performance

Answer 20

• baseball bat
• throw a shot put
• catching a ball
• the ground
  (newtons third law)

Question 21

what is force summation

Answer 21

force summation occurs when all body parts act simultaneously In practice, the strongest and lowest body parts around the centre of gravity (e.g. trunk and thighs) move first, followed by the weaker, lighter, and faster extremities.

Question 22

what is simultaneous force summation, give a sporting example

Answer 22

• maximal force
• high jump

Question 23

what is sequential force summation, give a sporting example

Answer 23

body parts move in a sequence to produce the desired degree of force

Question 24

what is the difference between the two types of force summation

Question 25

what are the four rules of sequential force summation?

Answer 25

order- the large muscles groups before the small ones timing- each muscles are brought in at the same time stabilisation- the foot plants on the ground in a shot put throw to then enable maximal force

Question 26

what is angular motion

Answer 26

it is evident when a body or object turns about an axis of rotation.

Question 27

what is moment of inertia

Answer 27

the resistance of rotating body to change, particularly during its resistance to beginning rotation.

Question 28

what is angular velocity

Answer 28

time rate at which an object rotates, or revolves, about an axis, or at which the angular displacement between two bodies changes

Question 29

what is high inertia

Answer 29

more force has to be applied in order to cause a rotation

Question 30

what is low inertia

Answer 30

lower moments of inertia means that only low forces are necessary. Masses that are further away form the axis of rotation have the greatest moment of inertia.

Question 31

what is high angular velocity

Question 32

what is low angular velocity

Question 33

what is the formula for angular momentum

Question 34

what is projectile motion

Question 35

what are the factors that effect the distance achieved by a projectile

Answer 35

- speed or velocity release - angle of release - height of release - gravity - air resistance

Question 36

what is the velocity/speed of release

Answer 36

the speed at which a projectile is released or launched

Question 37

what is the angle of release

Answer 37

is the angle of take-off of a projectile. theoretically the angle of release for achieving maximum distance is 45 degrees

Question 38

what is the height of release

Answer 38

is the vertical height above the point of landing which a projectile is released or launched. for any given velocity and angle of release, as the height of release increases, the distance achieved increases.

Question 39

what is gravity

Answer 39

gravity is a constant force that acts on all projectiles by pulling them towards the earth at the rate of 9.8 metres per second

Question 40

what is air resistance

Answer 40

air resistance is the resistance to motion of a projectile created by the air through which the projectile must travel

Question 41

what are the factors affecting air resistance

Answer 41

- the projectiles shape - velocity - increased velocity, increased air resistance - mass or weight

Question 42

what does it mean to use air resistance to gain an advantage

Question 43

what is the projectiles shape

Answer 43

blunt-shaped objects passing through the air experience greater air resistance than streamlined tapered shapes. it is for this reason that aircraft are designed with a tapered front, narrow leading edges and a streamlines fuselage. this also applies to a design of racing cars and, more recently, bicycles.

Question 44

what is the projectiles velocity

Answer 44

air resistance is greater at higher velocities. a ball thrown at high velocity will experience greater air resistance than a ball thrown gently. this is seen when throwing beach balls around.

Question 45

what is the projectiles mass or weight

Answer 45

air resistance has a greater effect on lighter objects as opposed to heavier objects. this is seen when dropping objects of different mass and shape from a height