Mechanics: Unit 1 Motion (class + online)

Question 1

What is mechanics?

Answer 1

a branch of physics that analyses the action of forces on matter or material bodies

Question 2

What is force?

Answer 2

something that displaces and/or deforms a body

Question 3

What can statics be used for?

Answer 3

to calculate unknown forces

Question 4

Which of kinetics and kinematics considers force?

Answer 4

kinetics

Question 5

What is kinematics?

Answer 5

it quantifies motion by how it moves in 3d space

Question 6

What is kinetics?

Answer 6

looks at the relationship between force and motion

Question 7

What are the two areas of mechanics?

Answer 7

rigid and deformable body

Question 8

In classical mechanics, what do the terms
a) reductionistic
b) deterministic
mean?

Answer 8

a) reducing a complex problem into simpler parts

b) if we have a set of initial conditions we can work forward/bckward and distinguish a solution

Question 9

What is a translational movement?

Answer 9

a linear movement ie. in a straight line

Question 10

What is the difference between rectilinear and curvilinear?

Answer 10

rectilinear is an actual straight line whereas curvilinear isnt perfectly straight but there is no rotation

Question 11

What do rotary movements in walking allow for?

Answer 11

linear movement of the whole body

Question 12

What system is used for measurement?

Answer 12

SI aka metric

Question 13

How do we measure

a) length
b) time
c) mass

Answer 13

a) metre
b) second
c) kilogram

Question 14

how many metres in

a) km
b) cm
c) mm
d) micrometre

Answer 14

a) 1000
b) 0.01
c) 0.001
d) 0.000001

Question 15

what is angular distance and which SI unit does it use?

Answer 15

the total angle turned through

rads

Question 16

what is a rad ? and what is it equal to?

Answer 16

2 π rads = 360

about 57 degrees

one radian encloses an arc which has a length equal to the circle radius

Question 17

what is a newton?

Answer 17

kilogram metres per second squared

kg m s-2

Question 18

what are the four basic physical quantities?

Answer 18

time
angle
temperature
distance

Question 19

What symbol represents

a) angle in degrees?
b) angle in rads?

Answer 19

a) phi Φ

b) theta θ

Question 20

How do we convert radians to degrees ?

Answer 20

degrees = (radians x180/ π)

Question 21

How do we convert degrees to radians?

Answer 21

radians = (degrees xπ /180)

Question 22

What does zero degrees kelvin represent?

Answer 22

the point at which matter has no energy

Question 23

How can you convert celsius to kelvin?

Answer 23

add 273

Question 24

What are positions and directions given in reference to?

Answer 24

a reference frame

Question 25

What are the two co-ordinate systems that positions in reference frames are related to?

Answer 25

the rectangular co-ordinate system or the polar co-ordinate system.

Question 26

What is another name for the rectangular reference frame?

Answer 26

cartesian

Question 27

What is a vector?

Answer 27

a quantity with magnitude (length) and direction

Question 28

What is a scalar?

Answer 28

a quantity with only magnitude

Question 29

Name some vectors

Answer 29

``` displacement (inc angular) velocity (inc angular) force momentum acceleration ```

Question 30

Name some scalars

Answer 30

``` distance speed angle rotation rate mass temperature energy ```

Question 31

What is the difference between distance and displacement?

Answer 31

distance is a scalar because it is just a measure of how far but displacement is a vector because it also takes direction into account

Question 32

What is angular displacement?

Answer 32

when something is rotated through an angle in a clockwise or anticlockwise direction has both a magnitude and a direction

Question 33

How do you add or subtract two or more vectors?

Answer 33

via graphs or trigonometry to give a resultant vector

Question 34

When resolving a vector, if the resultant vector faces a) north west (ie. positive vertical but negative horizontal) b) south west (ie. negative vertical and horizontal) how do we calculate the angle?

Answer 34

a) +180 | b) -180

Question 35

What do you call axes which are all at right angles to each other?

Answer 35

orthogonal

Question 36

in which type of system does a change in one axis not affect the others?

Answer 36

orthogonal

Question 37

describe a plane

Answer 37

a 2d structure with no thickness encompassing 2 axes of a 3D co-ordinate system

Question 38

what happens when 2 planes cross each other?

Answer 38

a straight line is formed

Question 39

how many planes can be at right angles to each other?

Answer 39

max is 3

Question 40

how is position expressed in the polar coordinates system for 2D structures?

Answer 40

(rc, θc) where rc = length of line θc = angle of line

Question 41

When are polar co-ordinates more useful than rectangular co-ordinates?

Answer 41

in the studies of circular objects and where angles and rotations are important

Question 42

What is the origin?

Answer 42

the point where all axes cross (0,0,0)

Question 43

What is the difference between speed and velocity?

Answer 43

speed is a scalar, the rate of change of distance travelled velocity is a vector, the rate of change of displacement (so direction is included)

Question 44

What are the SI units of velocity?

Answer 44

metres per second (m s-1)

Question 45

how do you work out the average velocity?

Answer 45

change in displacement over time

Question 46

What is acceleration?

Answer 46

the rate of change of velocity

Question 47

Is acceleration a scalar or a vector quantity?

Answer 47

a vector quantity

Question 48

What are the SI units of acceleration?

Answer 48

m s-2

Question 49

What is the SI unit of force?

Answer 49

the newton (N)

Question 50

how is position expressed in the polar coordinates system for 3D structures?

Answer 50

(rc, θc, Φc )

Question 51

What do we call the movement of an object in a straight line with no rotation taking place?

Answer 51

translation

Question 52

What do we call the movement of an object in a circular path with no translation taking place?

Answer 52

a rotation

Question 53

How many degrees of freedom does unconstrained movement have?

Answer 53

6 degrees of freedom - 3 translational (x,y,z) - 3 rotational

Question 54

how many degrees of freedom does a snooker ball have rolling on a table?

Answer 54

5 degrees of freedom - 2 translational - 3 rotational

Question 55

how many degrees of freedom does a door handle have?

Answer 55

1 rotational

Question 56

compare the degrees of freedom of a ball and socket joint to a hinge joint?

Answer 56

ball and socket eg hip has 3 rotational | hinge joint eg knee has 1 rotational

Question 57

How do we display velocity data?

Answer 57

displacement-time graphs | with velocity being equal to the gradient

Question 58

What is instantaneous velocity and how do we work it out?

Answer 58

it is the velocity at an instant in time it is equal to the gradient on the displacement-time graph at a certain point work it out by drawing a tangent

Question 59

How do we work out average acceleration?

Answer 59

change in velocity over time | = ms-2

Question 60

What is the acceleration of something falling due to gravity?

Answer 60

9.81m/s2

Question 61

How do we display acceleration data?

Answer 61

velocity-time graph

Question 62

What is the gradient of the velocity-time graph equal to?

Answer 62

acceleration

Question 63

What is the area under the velocity-time curve equal to?

Answer 63

total displacement ie the velocity

Question 64

What are the four parameters used to describe rotary motion?

Answer 64

time angular displacement angular velocity angular acceleration

Question 65

What does the symbol a represent?

Answer 65

alpha is used to represent angular acceleration (rad/s2)

Question 66

what does the symbol ω represent?

Answer 66

omega is used to represent angular velocity (rad/s)

Question 67

what is angular velocity?

Answer 67

the angular displacement travelled per second

Question 68

how can we find the angular velocity?

Answer 68

plotting an angle-time graph

Question 69

what is angular acceleration?

Answer 69

the rate of change of angular velocity

Question 70

what is the gradient of an angular velocity-time graph equal to?

Answer 70

angular acceleration

Question 71

``` what do a) u b) v c) a d) s e) t represent in the equations of linear motion? ```

Answer 71

a) starting velocity b) final velocity c) acceleration d) displacement e) time taken

Question 72

How can we calculate final velocity?

Answer 72

v = u + at | final velocity = starting velocity + (acceleration x time)

Question 73

Give 3 linear equations including displacement

Answer 73

v2 = u2 + 2as s = 1/2 ( u + v) t s= ut + 1/2 a t2

Question 74

What is the multiplication factor for the prefix giga?

Answer 74

10 to the 9

Question 75

What is the multiplication factor for the prefix mega ?

Answer 75

10 the 6

Question 76

What is the multiplication factor for the prefix kilo?

Answer 76

10 to the 3

Question 77

What is the multiplication factor for the prefix centi?

Answer 77

10 to the -2

Question 78

What is the multiplication factor for the prefix milli?

Answer 78

10 to the -3

Question 79

What is the multiplication factor for the prefix micro?

Answer 79

10 to the -6

Question 80

What is the multiplication factor for the prefix nano?

Answer 80

10 to the -9

Question 81

What is the symbol for angular displacement?

Answer 81

θ

Question 82

How can we measure force?

Answer 82

calibrated spring balance