Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

alevel pe aqa > angular motion > Flashcards

angular motion Flashcards

1
Q

what is angular motion

A

it refers to rotation and involves turning around an axis

angular motion can be a whole body or a part of a body like arms or legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

examples of angular motion for a part of a body

A

throwing a discuss, arms and legs whist running, forehand in tennis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how do we create a turning force

A

we apply the force eccentrically

eccentric forces create more torque

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

angular motion occurs as a result of…

A

torque

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is torque

A

it is a turning force that causes an object to rotate around its axis

often called a moment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

a formula that involves torque

moment of force=

A

moment of force (torque-newton meters) = force (N) x perpendicular distance from fulcrum (m)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

if you increase the size of the force it increases torque what happens to angular motion

A

it is increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how can torque be changed to have different effects on angular motion

A

if it is applied closer to or further away from the axis of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what affect does perpendicular distance from fulcrum (pivotal point) have on torque

A

the greater the distance the the more we multiply by and so the greater the torque

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is newtons first law in relation to AM

A

a rotating body will continue to turn about its axis of rotation with constant angular momentum unless an external rotational force (torque) is exerted upon it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is newtons first law in relation to AM applied to a figure skater

A

spinning in flight they will continue to spin until they land and an external force is applied onto their skates this will change and slow their angular momentum, this force will be friction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is newtons 2nd law in relation to AM

A

the rate of change of angular momentum of a body is proportional to the force (torque) causing it and the change takes place in the direction in which the force (torque) acts

the greater torque (turning force) exerted the faster the rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the moment of force =

(2nd)

A

moment of force (torque-newton meters)= force (newtons) X perpendicular distance from fulcrum (pivotal point) (m)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

apply newtons 2nd law in relation to AM for lacrosse sticks

A

with a longer stick (defense) there is a longer perpendicular distance from the fulcrum so you can propel the ball with the most force

shortest stick (attack/midfield) there is a shorter perpendicular distance from the fulcrum so it allows more control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is newtons 3rd law in relation to AM

A

when a force (torque) is applied by one body to another the second body will exert an equal and opposite force (torque)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

apply newtons 3rd law in relation to AM for a tennis lpayer

A

a tennis player applies a downwards slice action on the ball it will rotate (spin) to replicate the amount of torque provided

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is angular displacement

A

the smallest change in angle between the starting and finishing point of rotation

the change in the angle as an object moves in a circular path

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how many degrees is 1 radian

A

57.3 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

is angular displacement a scalar or vector

A

vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how many degrees is 1 radian

A

57.3 degrees

19
Q

how many radians/the angular displacement of 360 degrees (inc working out)

A

360 degrees is not zero displacement
360/57.3=6.28 radians

20
Q

formula for angular displacement

A

angular displacement=angular velocity x time taken

21
Q

what is angular velocity

A

rotational speed of the object, rate of change of angular displacement

ms: AV is the rate of rotation of a body around its axes of rotation.

22
Q

is angular velocity a scalar or vector and why

A

vector because it refers to the angular displacement that is covered in a certain time

23
Q

formula for angular velocity

A

angular velocity= angular displacement (rad)/time taken

24
Q

a performer spins from one position to another on the parallel bars, spinning 110 degrees from point x to y in 0.5 secs, what is the angular velocity

A

AD= 110/57.3 = 1.9 rads displacement

1.9/0.5 = 3.8 rad/s

25
Q

what is moment of inertia

A

the resistance of a body to angular motion (spin)
reluctance to change its current state of rotational motion

level of force that has to be applied in order to maintain inertia

ms: MOI is the bodys reluctance to rotation/to alter rate of rotation

26
Q

what can the moment of inertia depend on

A

the mass of the body and the distribution of mass around the axis of rotation

both can be manipulated

27
Q

how can mass affect the moment of inertia

A

the greater the mass the greater the resistance to change and therefore the greater moment of inertia

28
Q

how can the distribution of mass affect the moment of inertia

A

the closer the mass is to the axis of rotation the easier it is to rotate, this is because the moment of inertia is lower, increasing the distribution of mass away from the axis of rotation will increase the reluctance to rotate (increasing moment of inertia)

29
Q

formula for moment of inertia

A

body mass x distance from axis of rotation ^2

kg m^2

30
Q

what is angular momentum

A

the amount of angular motion of an object when turning
quantity of rotation

31
Q

what is the conservation of angular momentum

A

angular momentum is conserved when a body is in flight and there is an inversely proportional relationship between angular velocity and moment of inertia

it stays constant unless external force (torque) is applied (n1st law)

ms: the principle of COAM states that AM remains constant, if MOI decreases, AV increases and vice versa

32
Q

formula for angular momentum

A

moment of inertia (kg m^2) x angular velocity rads/s

kg m^2 / rads sec

33
Q

what is angular acceleration

A

the rate of change of angular velocity

34
Q

formula for angular acceleration

A

change in AV (rad/s)/time taken ^2

rad/s^2

35
Q

to increase angular velocity what do you do

A

increase the moment of inertia
distributing the mass further away from the centre of gravity

spread out the body

36
Q

to decrease angular velocity what do you do

A

decrease moment of inertia
distributing the mass closer to the centre of gravity

tuck the body in

37
Q

apply the moment of inertia to a sprinter

A

driving leg (extending) is far from the hip and therefore has a large moment of inertia

the recovery leg that flexes allows its mass to travel closer to the axis of rotation and therefore moves quicker as it reduces to the moment of inertia

38
Q

gymnasts have to change the position of their body when performing a somersault during a floor routine

explain how a gymnast alters their angular velocity by changing their moment of inertia (4)

A

angular momentum= moment of inertia x angular velocity (during rotation)
angular momentum remains constant/conservation of angular
momentum.

to slow down (rotation) gymnast increases moment of inertia.

achieved by extending body/opening out/or equivalent

to increase speed of rotation gymnast decreases moment of inertia

achieved by tucking/bringing arms towards rotational axis

39
Q

explain how a gymnast can alter the speed of rotation during flight (8 marks)

A

changing shape of the body will causes a change in speed.
change in moi leads to change in av/speed of rotation.
angular mom remains constant
angular mom=moi x av
av is speed of rotation
moi- distribution of mass around axis/reluctance of the body to move.
to slow down rotation increase moi done by extending out body.
to increase speed decreases moi achieved by tucking the body in.

draw diagram

40
Q

analyse how newtons laws of angular motion can account for the figure skaters speed of rotation throughout the movement (3)

1st law…

A

the ice skater will rotate with constant angular momentum in the air if there is no external torque/rotational force slowing them down until they land back on the ice

41
Q

analyse how newtons laws of angular motion can account for the figure skaters speed of rotation throughout the movement (3)

2nd law…

A

the more torque/rotational force the skater pushes off the ice the faster they will rotate allowing them to complete their rotations before returning to the ice

42
Q

analyse how newtons laws of angular motion can account for the figure skaters speed of rotation throughout the movement (3)

3rd law…

A

when the rotating skater lands back on the ice the torque they apply to the ice is returned to them slowing them down

at take off the skater will apply torque to the ice which will generate torque in the opposite direction causing the skater to rotate.

43
Q

analyse how the gymnast makes use of the principle of conservation of angular momentum when performing to a front tuck somersault. refer to the graph above in the answer (graph being that on COAM) (15)

AO1:

A

AM is the quantity of rotation a body possesses and is a product of MOI x AV > = AM

MOI is the bodys reluctance to rotation/to alter rate of rotation

AV is the rate of rotation of a body around its axes of rotation.

AA is the rate of change of AV.

the principle of COAM states that AM remains constant, if MOI decreases, AV increases and vice versa

44
Q

analyse how the gymnast makes use of the principle of conservation of angular momentum when performing to a front tuck somersault. refer to the graph above in the answer (graph being that on COAM) (15)

AO2:

A

MOI is high at the start and the end of the somersault but low in the middle of the movement.

AV is low at both the start and end but high in the middle. start and end/go into/out of somersault, slowing the rate of rotation

AA is occurring as the performer begins the somersault and angular deceleration occurs as they complete the somersault.

AM remains constant

45
Q

analyse how the gymnast makes use of the principle of conservation of angular momentum when performing to a front tuck somersault. refer to the graph above in the answer (graph being that on COAM) (15)

AO3:

A

gymnast is in an open position initially = large MOI = low AV

gets into tucked position > mass is distributed closer to their COM = reduced MOI, increased AV

AA as a result of reduced MOI and increased AV > full rotation to occur quickly > time to land safely

opens out from tuck = MOI increases, mass is further from COM, AV decreases (AD) > slow down prior to land = control maintained.

AM remains constant as they manipulate their body to reduce MOI and increase AV whilst maintaining AM

46
Q

explain newtons laws of motion in relation to the dancer spinning and how the dancer can alter her rate of spin (15) newtons first law 1, 2, 3

A

AO1: states that a body will continue to turn about its axis of rotation with constant angular momentum unless a force is exerted upon it

AO2: therefore dancer will continue to spin with constant angular mom unless an external force acts on her

AO3: this is known as the principle of conservation of AM. the dancer can alter her rate of spin by moving her limbs either closer or further away from the axis of rotation there fore to increase her rate of spin she will need to bring her arms close to her body, without this ability she will be unable to control the movement.

if she as failed to warm up appropriately she will not be unable to achieve the most efficient position, making the spin more difficult to perform with a reduction in potential o2 delivery due to lack of suitable warm up she will fatigue more quickly reducing her ability to control spin.

47
Q
A

alevel pe aqa (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions