Intro to Biomechanics

Question 1

newtons first law

Answer 1

An object will remain at rest or in some uniform motion in a straight line unless some net external force acts upon it.

Question 2

inertia

Answer 2

This tendency to remain in its current state

Question 3

force is ..

Answer 3

vector quantity.

Question 4

The total or ___ acting on an object is the ___acting on the object.

Answer 4

The total or net force acting on an object is the vector sum of all the forces acting on the object.

Question 5

newtons second law

Answer 5

The acceleration (a) of an object is directly proportional to the net external force (F) exerted on it, and inversely proportional to its mass (m)

Question 6

newtons second law equation

Answer 6

F = ma
m = mass
F= External force
a = acceleration

Question 7

kinematics

Answer 7

study of motions

Question 8

statics

Answer 8

mechanics of fixed systems

Question 9

units of forces

Answer 9

are kg m s-2 or Newton (N).

Question 10

mechanics is essential to understand

Answer 10

Joint articulation
Stability and balance
Structure and function of bones
Weight and effective weight
Effect of impulse and impact
Effect of motion and acceleration

Question 11

An important force in biomechanics is the ___

Answer 11

An important force in biomechanics is the gravitational force or weight

Question 12

why is weight calculated by mass x acceleration

Answer 12

Since the acceleration due to gravity (g) acts vertically downward, the gravitational force or weight (W) on an object of mass (m) is given by mass x acceleration,

Question 13

weight formula

Answer 13

m(mass) x g(gravity)

Question 14

newtons third law

Answer 14

If an object exerts a force (F) on a second object, then the second object exerts an equal in magnitude, but opposite in direction force (-F) on the first object.

Question 15

acceleration

Answer 15

change of velocity

Question 16

quantity vector

Answer 16

direction and magnitude

Question 17

the ability for the body to withstand large accelerations is dependant on what

Answer 17

on magnitude and duration of acceleration

Question 18

why is the ability to withstand large acceleration dependant on its duration and magnitude

Answer 18

This is due mainly to the structural strength of the bone structures, as well as the inertia of the blood and internal organs

Question 19

inertia

Answer 19

can displace organs when large acceleration

Question 20

examples of physiological effects from large acceleration

Answer 20

heart struggles to pump blood w/ effective weight
reduced blood pressure in retina
sensitive to O2 deprivation - possible blackout
reduced blood pressure in brain - possible unconsciousness

Question 21

momentum

Answer 21

mass x velocity

vector quantity

Question 22

units of momentum

Answer 22

kg m s-1

Question 23

principle of conservation of linear momentum

Answer 23

‘If there is no external force applied to a system then the total linear momentum of that system remains constant in time
momentum = mass x velocity
if there is a change in velocity there is a force applied
If there is a change of momentum there will be impact force

Question 24

change in velocity means

Answer 24

force is applied

Question 25

impulse Ft

Answer 25

acceleration = (v2 - v1)/t newtons second law F =ma F = m(v2-v1)/t Ft = m(v2-v1)/t

Question 26

how can the impact force of a car accident be reduced

Answer 26

impulse is fixed by the initial speed to 0(the collision) | impact force can be reduced by increasing the time over which the momentum changes

Question 27

how do we try to minimise impact force by increasing the time over the impact occurs

Answer 27

seat belt tightens after speed increases reduce impact force air bags -collision with it come to a stop/rest over a longer period of time than when it hits a windscreen crumple zone - infront and back of cars which design to collapse on impact - increase the time in which car comes to rest reduce speed - lower change in velocity

Question 28

whiplash

Answer 28

physical damage to the upper spinal column or muscles in the neck region due to inertia of the body resulting from an impact from either the front or rear.

Question 29

energy

Answer 29

The ability to do work

Question 30

conservaton of energy

Answer 30

Within a closed system, the total amount of energy is constant.

Question 31

energy is measured in

Answer 31

joules

Question 32

work

Answer 32

Work Done (W) on a body by a force (F) in moving the object through a distance (d) is given by

Question 33

work formula

Answer 33

W = F x d

Question 34

impulse

Answer 34

change of momentum

Question 35

work is a ...

Answer 35

vector quantity

Question 36

how else can work be calculated

Answer 36

distance moved in DIRECTION in which the force is applied | work done = Fcos0 x distance moved

Question 37

work can also be defined as

Answer 37

expenditure of energy | e.g. pushing against a wall or carrying a load in a stationary position still constitutes as work

Question 38

kinetic energy

Answer 38

energy due to an objects motion = 1/2mv^2 m =mass v= velocity

Question 39

potential energy

Answer 39

``` energy an object has due to its shape or position mgh m =mass g = gravity h = height ```

Question 40

work energy principle

Answer 40

The total Mechanical Energy of a system is the sum of the Kinetic and Potential energies. Total Mechanical Energy of a system at some time is EQUAL to the Total Mechanical Energy of the system at some later time +/- any Work Done on/by the system,

Question 41

an example of chemical energy important in our physiology

Answer 41

calorific energy associated with food

Question 42

metabolism

Answer 42

Normal bodily activity requires work to be expended

Question 43

BMR

Answer 43

1.22kCal/minute

Question 44

how many calories used a day

Answer 44

1750kCal/day

Question 45

power calculation

Answer 45

work done/time

Question 46

power definition

Answer 46

the rate at which energy is expended and is defined as follows:

Question 47

efficiency

Answer 47

the ratio of the work done on the required activity to the TOTAL energy expended

Question 47

efficiency

Answer 47

the ratio of the work done on the required activity to the TOTAL energy expended