Bio mechanics module 1 - sem1

Question 1

what are SI units

Answer 1

internationally agreed standard units of measurement

Question 2

examples of SI units

Answer 2

metre (m)
second (s)
kilogram (kg)
kelvin K

Question 3

what are derived units

Answer 3

formed by combining base units
e.g. newton for force

Question 4

example of a supplementary unit

Answer 4

rad, for radian

Question 5

how to convert radian to degree

Answer 5

radian x (180/pi)

Question 6

how to convert degree to radian

Answer 6

degree x (pi/180)

Question 7

how to convert from celcius to kelvin

Answer 7

add 273

Question 8

what is the origin

Answer 8

where all axes cross (0,0,0)

Question 9

name the 3 planes

Answer 9

sagittal
coronal
transverse

Question 10

what is a plane

Answer 10

a flat, 2 dimensional surface

Question 11

what is a vector quantity

Answer 11

has both magnitude and direction

Question 12

what is a scalar quality

Answer 12

only has magnitude (size)

Question 13

examples of vector quantities

Answer 13

displacement, velocity, acceleration, force

Question 14

example of scalar qualities

Answer 14

speed, distance, time, mass

Question 15

what effects will a force have on an object

Answer 15

change the position
deform the shape

Question 16

what is static equilibrium

Answer 16

An object with static equilibrium is said to have no resultant force (or moment) acting on it and is said to be in static equilibrium.

Question 17

what is the condition of static equilibrium

Answer 17

The first condition of static equilibrium is that the sum of all the external forces (F) acting on an object is zero.

Question 18

what is newtons third law

Answer 18

to every action, there is an equal and opposite reaction

Question 19

what is an external force

Answer 19

force acting on a body from outside it

Question 20

examples of external forces

Answer 20

gravity, friction , reaction forces

Question 21

what is mass

Answer 21

the quantity of matter which a body is composed of

Question 22

what is weight

Answer 22

the force of gravity acting on a body
W = mg

Question 23

what is density

Answer 23

The density of a material is equal to the mass per unit volume

Question 24

does density remain constant or vary proportionately

Answer 24

remains constant

Question 25

units of density

Answer 25

kg m-3

Question 26

what is gravity

Answer 26

acceleration due to the gravitational attraction between two bodies results in weight

Question 27

what is the centre of mass

Answer 27

point where all the mass of an object can be presumed to act

Question 28

rule for centre of gravity

Answer 28

can only exist inside a gravitational field

Question 29

what is pressure

Answer 29

force exerted per unit area pressure = force / area

Question 30

SI unit for pressure

Answer 30

pascal, Pa

Question 31

what is a moment

Answer 31

the tendency of a force to produce rotation about an axis

Question 32

formula for moment

Answer 32

M = Fd distance / radius

Question 33

what is a lever

Answer 33

rigid bar pivoting around a fulcrum consists of effort force and resistance force

Question 34

calculation for mechanical advantage

Answer 34

effort arm / resistance arm

Question 35

what is a mechanical advantage

Answer 35

>1, resistance arm > effort arm

Question 36

what is a mechanical disadvantage

Answer 36

<1 , effort arm > resistance arm

Question 37

describe a first class lever system

Answer 37

fulcrum is located inbetween the effort arm and resistance arm works at either mechanical advantage or disadvantage e.g. see-saw

Question 38

describe a second class lever system

Answer 38

resistance arm is located inbetween the fulcrum and effort arm always works at mechanical advantage e,g. wheelbarrow

Question 39

describe a third class lever system

Answer 39

effort arm is located inbetween the fulcrum and the resistance arm always works at a mechanical disadvantage e.g. tweezers

Question 40

why does the musculoskeletal system mostly work at a mechanical disadvantage

Answer 40

the forces produced by the muscles are greater than the forces resisting them This is because the muscles insertion points tend to be closer to the fulcrum than the resistance force.