Biomechanics class test 2 revision Flashcards Preview

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Flashcards in Biomechanics class test 2 revision Deck (31):
1

Newtons 1st law

A body continues in a state of rest or constant velocity unless acted upon by an external force

2

Newtons 2nd law

Law of a acceleration
Force= mass x accelerate
The rate of change of motion is proportional to the force acting on it and is in the direction that the force acts

3

Newtons 3rd law

Action reaction
For every action, there is an equal and opposite reaction
Or for every force that is exerted by one body on another there is an equal and opposite force exerted by the second boy on the first

4

What is kinematics?

describes motion in terms of time and space

5

What is kinetics?

Examins the forces

6

Centre of gravity

w= m x g
Bodies are composed of particles
Each particle experiences an attraction towards the centre of the earth

7

Newtons law of gravitation

Every particle in the universe attracts every other particle with an attractive force

8

External forces

Act on objects as a results of interaction with surrounding environment
Contact/surface forces
Non contact forces

9

Internal forces

Act within object
Do not accelerate the body

10

Force platforms

Measure the whole body forces generated
Measurement of the force- newtons 3rd law
Force plates traducers convert the force exerted on it into an electrical signal

11

Scalar

Just magnitude

12

Vector

Magnitude and direction

13

Eccentric force

A force whose line of action does not pass through the centre of gravity
changes both angular and linear motion

14

Concentric force

A force whose line of action passes through the centre of gravity
change in linear

15

Adding scalars

Add the amounts

16

Adding vectors- triangle rule

Obtain the resultant by drawing the 2 vectors then forming the resultant by connecting the tail of the 1st with the tip of the second

17

Adding vectors- parallelogram law

sum of the 2 vectors- the diagonal of the parallelogram

18

Free body diagram

show all the external forces
Forces drawn as vectors
The tail is normally placed at the forces point of application

19

Equilibrium

Describes the state of a system that is not changing its speed or direction

20

Static equilibrium

Equilibrium for a body at rest

21

Dynamic equilibrium

Equilibrium for a body that has unchanging speed or direction

22

Stability

Refers to the state of equilibrium
Ability of a body to maintain its beginning static equilibrium posture

23

Base of support

The area made with the part of the body touching supporting surface

24

Stable equilibrium

Small perturbation- tends to return to original position

25

Unstable equilibrium

Small perturbation- tends to accelerate away

26

Neutral equilibrium

Neither returns or accelerates

27

Human body as a projector

Centre of mass will follow path regardless of changes of body configuration

28

Momentum

mass x velocity
kg.m/sec
Faster and larger the body, greater momentum

29

Principle of conservation of linear momentum

in any system where bodies collide or exert a force upon each other , the total momentum remains constant unless unbalanced external forces act as a system

30

Impulse N.sec

Force x time

31

Force equation

mass x acceleration