Linear Motion, angular motion, fluid mechanics and projectile motion (1.3b) Flashcards
1
Q
linear motion is….
A
movement of a body in a straight line where all parts move the same distance in the same direction over the same time
2
Q
direct force is….
and what does it result in?
A
a force applied through the centre of mass resulting in linear motion
3
Q
in a distance time graph the gradient of the curve indicates the…
A
speed of the body
4
Q
in a speed time graph the gradient of the curve indicates the…
A
acceleration or decleration of the body
5
Q
in a velocity time graph the gradient of the curve indicates the…
A
acceleration or deceleration of the body
6
Q
angular motion results from an…
A
eccentric force being applied to a body outside its centre of mass
7
Q
torque is…
A
a measure of the turning force applied to a body
8
Q
the logitudinal axis runs from….
A
the top to the bottom of the body
9
Q
a practical example that uses the longitudinal axis is…
A
a trampolinist performs a full twist turn
10
Q
the transverse axis runs from…
A
side to side of the body
11
Q
a practical example that uses the transverse axis is…
A
a front somersalt
12
Q
the frontal axis runs from….
A
the front to back of the body
13
Q
a practical example that uses the frontal axis is….
A
a gymnast perfoms a cartwheel
14
Q
the three axis of rotation are…
A
longitudinal
transeverse
frontal
15
Q
angular analogue of moment of inertia is…
A
the resistance of a body to change its angular motion or rotation
16
Q
moment of inertia =
A
sum (mass x distribution of mass from axis of rotation^2)
17
Q
angular velocity is….
A
the rate of change in angular displacement or rate of rotation
18
Q
moment of inertia is measured in…
A
kgm^2
19
Q
angular velocity =
A
angular displacement / time taken
20
Q
angular velocity is measured in…
A
rad/s
21
Q
angular momentum is…
A
the quantity of angular motion possessed by a body
22
Q
angular momentum =
A
moment of inertia x angular velocity
23
Q
angular momentum is measured in…
A
kgm^2/s
24
Q
the two factors that affect moment of inertia are…
A
mass
ditribution of mass from the axis of rotation
25
what effect does mass have on moment of inertia?
the greater the mass the greater the moment of inertia, the harder it is to change the rate of rotation
26
what effect does distribution of mass from the axis of rotation have on moment of inertia?
the further the mass from the axis of rotation the greater the moment of inertia so there is more resistance to rotation
27
what affect does a high moment of inertia have on angular velocity?
the resistance to rotation is high therefore angular velocity is low and rate of spin is slow
28
what affect does a low moment of inertia have on angular velocity?
the resistance to rotation is low therefore angular velocity is high and rate of spin is fast
29
define conservation of angular momentum
angular momentum is a conserved quantity that remains constant unless an eccntric force or torque is applied
30
does angular momentum once generated change throughout movemrnt?
no
31
performers manipulate ___________ and _______ to maximise performance
moment of inertia
angular velocity
32
define the angular analogue of newtons first law of motion
(the angular equivalent of Newton's first law of motion)
a rotating body will continue to turn about an axis of rotation with a constant angular momentum unless acted on by an eccentric force or torque
33
define drag
the force that opposes the direction of motion of a body through water or air
34
the 4 factors that affect air resistance and drag are...
velocity
frontal cross-sectional area
streamlining and shape
surface characteristics
35
how does velocity affect air resistance and drag?
the greater the velocity, the greater the force of air resistance and drag opposing motion
36
how does a cyclists high velocity affect their air resistance?
their high velocity means their air resistance is high
37
how does frontal cross-sectional area affect air resistance and drag?
the greater the frontal cross-sectional area, the greater the air resistnace or drag
38
how does a downhill skiers crouched position affect air resistance and drag?
the low crouched position reduces their cross-sectional area reduces air resistance and drag
39
how does streamlining and shape affect air resistance and drag?
the more aerodynamic the shape of the body or equipment, the lower the air resistance or drag
40
how do surface characteristics affect air resistance or drag?
the smoother the surface, the lower the air resistance or drag
41
how do cyclists use surface characteristics to decrease drag or air resistance?
they wear lycra suits to make the surface smoother
42
projectile motion is.....
the movement of a body through the air following a curved flight path under the force of gravity
43
a projectile is....
a body that is launched into the air, losing contact with the ground surface
44
the 4 factors that affect the horizontal distance travelled by a projectile are...
speed of release
angle of release
height of release
aerodynamic factors
45
how does speed of release affect the horizontal distance travelled by a projectile?
the greater the speed of release of the projectile the further it will travel
46
how does angle of release affect the horizontal distace travelled by a projectile?
45 degrees is the optimal angle of release for the furthest horizontal distance
47
when height of release is higher than the landing height how is the angle of release affected?
where release height is higher than angle height the optimal angle is less than 45 degrees.
48
how does height of release is lower than the landing height how is the angle of release affected?
where release height is lower than landing height the optimal angle is greater than 45 dgrees
49
which aerodynamic factors affect horizontal distance travelled by a projectile?
bernoulli's and magnus
50
a parabola is....
a uniform curve symmetrical about its highest point
51
a parabolic flight path is...
a flight path symmetrical about its highest point caused by the dominant weight force of a projectile
52
if weight is the dominant force and air resistance is small a _______ flight path occurs
parabolic
53
give and explain a practical example of a parabolic flight path
a shot put
it has a high mass and travels through the air with a low velocity with a small frontal cross sectional area and smooth surface area minimising air resistance minimal
54
a non parabolic flight path is....
a flight path asymmetrical about its highest point caued bythe dominant force of air resistance on a projectile
55
if air resistance is the dominant force and weight is very small a __________ flight path occurs
non-parabolic
56
give and explain a practical example of a non-parabolic flight path
a badminton shuttle
it has a very low mass and travles at a high velocity with an uneven surface which increases air resistance
57
in a parabolic flight path what force is dominant?
wieght
58
in a non parabolic flight path what force is dominant?
air resistance
59
a parallelogram of forces can be drawn to conisder...
the result of all forces acting on a aprojectile in flight
60
resultant force is..
the sum of all forces acting on a body or the net force acting on a projectile
61
in a parallelogram of forces if resultant force is closer to the weight arrow weight is _______
so the flight path will be _________
dominant
parabolic
62
in a parallelogram of forces if the resultant force is closer to the air resistance arrow, air resistance is ____
so the flight path will be _________
dominant
non-parabolic
63
the Bernoulli Principle is...
the creation of additional lift force on a projectile in flight resulting from Bernoulli's conclusion that the higher the velocity of air flow, the lower the surrounding pressure
64
lift force is...
an additional force created by a pressure gradient forming on opposing surfaces of an aerofoil moving through fluid
65
describe the shape of an aerofoil
a streamlined shape with a curved upper surface and a flat lower surface
66
angle of attack is...
17 degrees and is the most favourable angle of release for a projectile to optmise lift force due to the Bernoulli principle
67
how is lift force created?
6 marks
1. Create an angle of attack 17°
2. Air travels further over top of projectile
3. Air travels faster over top of projectile
4. Creating a pressure gradient
5. Air moves from area of high to low pressure
6. Lift force created
68
if the aerofoil is inverted what is generated?
downward lift force
69
what sport is upward lift force useful?
ski jumping
70
in what sport is downward lift force useful?
F1
71
how is downward lift force created?
5 marks
1. aerfoil shape is inverted
2. air is forced to travel a further distance underneath projectile
3. air velocity underneath projectile increases creating low pressure
4. a pressure gradient is formed
5. resulting in downward force
72
where is eccentric force applied to to create a topsin?
above the COM
73
how does the projectile spin in a topspin?
downwards around a transverse axis
74
where is eccentric force applied in a backspin?
below the COM
75
how does the projectile spin in a backspin?
upwards around the transverse axis
76
where is the eccentric force applied in a sidespin hook?
right of the COM
77
how does the projectile spin in a sidespin hook?
left around the longitudinal axis `
78
where is the eccentric force applied in a sidespin slice?
left of the COM
79
how does a the projectile spin in a sidespin slice?
right around the longitudinal axis
80
magnus force is...
a force created from a pressure gradient on opposing surfaces of a spinning body moving through the air
81
magnus effect is....
creation of an additional Magus force on a spinning projectile which deviates the flight path
82
a hook is...
a type of sidespin used to deviate a projectile's flight path to the left
83
a slice is....
a type of sidespin used to deviate a projectiles flight path to the right
84
topspin tennis example
for a ball with topspin the additional magnus force is created by....
1. the upper surface of a ball rotates towards the oncoming air flow, opposing motion, decreasing velocity of air flow and creates a high pressure zone
2. the lower surface of the ball rotating in the same direction as the air flow, increasing velocity of air flow and creates a low pressure zone
3. a pressure gradient forms and an additional Magnus force being created downwards
85
benefits of a spin in tennis
1. gives the ball stability in flight
2. can confuse the opposition
3. it shortens the flight path, allowing the ball to be hit harder without going out
86
describe how magnus force acts in a sidespin hook
5 marks
1. air flow opposes motion
2. ball rotates to the left guiding air flow at high velocity & low pressure
3. ball rotates against air flow on right resisting air flow at low velocity & high pressure
4. pressure gradient forms
5. magnus force acts to deviate the flight path left
87
describe how magnus force acts in a sidespin slice
5 marks
1. air flow opposes motion
2. ball rotates to the right guiding air flow at high velocity & low pressure
3. ball rotates against air flow on leeft resisting air flow at low velocity & high pressure
4. pressure gradient forms
5. magnus force acts to deviate the flight path right
