biomechanics

Question 1

what are Newton’s three laws?

Answer 1

1.law of inertia
2.law of acceleration
3.law of action/ reaction

Question 2

1.what is the law of inertia?

Answer 2

the bigger the mass, the larger the inertia, meaning more force is needed to change it’s state of motion.

Question 3

2. What is the law of acceleration?

Answer 3

the rate of acceleration is proportional to the force causing it and the change that takes place in the direction in which the force acts.

Question 4

3. what is the law of action/reaction?

Answer 4

For every action, there is an equal and opposite reaction.

Question 5

what is ground reaction force?

Answer 5

This is the force exeterted on the ground by the body.

Question 6

measurement triangle:

Answer 6

d/s*t

Question 7

what is the centre of mass?

Answer 7

the point of balance of a body.

Question 8

men and women’s COM?

Answer 8

men carry most their weight in the shoulders so the com is higher, women carry most their weight in their hips so it is lower.

Question 9

Factors affecting stability: the height of the centre of mass

Answer 9

lowering the centre of mass will increase stability.

Question 10

Factors affecting stability: position of line of gravity

Answer 10

the line of gravity should be central over the base of support to increase stability.

Question 11

Factors affecting stability: area of support base

Answer 11

the more contact points, the larger the base of support, increasing stability.

Question 12

Factors affecting stability: mass of the performer.

Answer 12

the greater the mass, the more stability because of an increased inertia.

Question 13

fosbury flop

Answer 13

it enable mass to be under the bar, while the body goes over. this is beneficial as the performer does not have to lift their com a great distance to clear the bar.

Question 14

structure of levers:

Answer 14

bones- lever
joints-fulcrum
muscles-effort
weight-resistance

Question 15

acronym for levers:

Answer 15

1 2 3
F R E
T G B
(tricep) (gastro- (bicep)
cnemius)
(ankle)

Question 16

acronym for arrows:

Answer 16

1st down (above line)

2nd up (below line)

3rd up (below line)

1st class people are above 2nd/3rd class and look down on them.

Question 17

what is resistance arm?

Answer 17

the distance from the resistance to the fulrum.

Question 18

what is effort arm?

Answer 18

the distance from the effort arm to the fulcrum.

Question 19

what’s the advantages and disadvantages of a 2nd class lever?

Answer 19

+generate much larger force, +overcome heavy loads.

-slow
-limited rom

Question 20

what’s the advantages and disadvantages of a 1st/3rd class lever?

Answer 20

+large rom
+resistance can be moved quickly

-can not apply much force to move
-harder to overcome a heavy load

Question 21

If the effort arm is longer than the resistance arm what does it mean?

Answer 21

there is a mechanical advantage.

Question 22

Linear motion diagram line meanings:

Answer 22

-The length of the arrow shows magnitude.
-The longer the arrow, the bigger the size.
-The direction is shown by the line of application.

Question 23

What is mass + equation?

Answer 23

Mass is the physical quantity of matter in the body. It is scalar.

Mass (n) * Gravity (9.8) = Weight (n)

Question 24

Equation for distance?

Answer 24

Distance= speed * time

Question 25

What is velocity + equation?

Answer 25

How fast the body travels in a certain direction, it’s the rate of change of displacement.

velocity (m/s) = displacement (m) / time (s)

Question 26

Graphs for distance:

Answer 26

1. stationary
2. change in direction
3. accelerating
4. decelerating

Question 27

Graphs for velocity:

Answer 27

1. Constant velocity
2. Increasing velocity
3. Decreasing velocity

Question 28

Equation for average acceleration:

Answer 28

Average acceleration (m/s2) =
change in velocity (final-initial) / Time

Question 29

What is momentum + equation?

Answer 29

The mass and velocity of an object.

Momentum (kgm/s) = mass (kg) * velocity (m/s)

Question 30

The greater the mass and velocity…

Answer 30

the greater the momentum.

Question 31

What is the conservation of momentum?

Answer 31

This occurs when an object is in flight, neither mass nor velocity is altered, so the mass is constant and unchanged.

Velocity however can be altered by external forces e.g. gravity, air.

Question 32

What is an internal force?

Answer 32

generated by the skeletal muscles.

Question 33

What is an external force?

Answer 33

comes from outside the body. e.g., air resistance, friction, weight.

Question 34

what is a static horizontal force? friction

Answer 34

force exerted when there is no motion between 2 surfaces.

Question 35

what is a sliding horizontal force? friction

Answer 35

when 2 bodies in contact have a tendency to slip/slide.

Question 36

3 factors affecting friction

Answer 36

1. the roughness of the surface.
   2.the mass of an object.
2. temperature of the 2 surfaces.

Question 37

3 factors affecting air resistance

Answer 37

1. velocity of the moving body
2. the frontal cross sectional area of the moving body.
3. the shape and surface characteristics of the moving body.

Question 38

free body diagrams

Answer 38

-weight
-friction
-air resistance
-reaction

Question 39

what is a balanced force?

Answer 39

when there are 2 or more forces acting on the body that are equal in size but opposite in direction. Net force is 0.

Question 40

what is an unbalanced force?

Answer 40

when one force is acting in one direction and is larger than the force acting in the opposite direction.