linear motion Flashcards

forces acting on during LM, D+E+U scalars and vectors ,

1
Q

what is linear motion

A

Is the movement in a straight line or curve with all body parts moving the same distance at the same speed in the same direction

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2
Q

do projectiles show linear motion

A

yes

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3
Q

what is parabolic flight

A

a curve of a projectile

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4
Q

what is a vector

A

vectors are forces that have both a magnitude (size) and direction

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5
Q

what are scalar quantities

A

are when measurements are only described as a magnitude only

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6
Q

is mass a scalar or vector

A

scalar

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7
Q

what is an Internal force plus eg

A

An internal force is applied when our skeletal muscles contract

eg the force produced by the quadriceps when we jump

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8
Q

what is an External force plus egs

A

An external force comes from outside the body

for example friction, air resistance and weight (gravity)

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9
Q

identify and explain two external forces acting on the athlete in the photograph (an athlete performing a long jump) the jumping bit (4)

A

air resistance (1) this will be acting in the opposite direction of travel to the jumper/will depend on the velocity of the jumper/cross sectional area/the streamlining/shape of the jumper (1)

weight/gravity (1) this will be pulling the jumper downwards towards the sand pit/greater the mass of jumper=greater the weight force pulling them down

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10
Q

what are the vertical forces

A

weight, reaction force.

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11
Q

identify one vertical force and one horizontal force acting on a performer when running in a 100m sprint

A

vertical: weight/(ground) reaction force/gravity

horizontal: friction/air resistance

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12
Q

what is reaction force

A

whenever forces act on a performer there will always be a reaction force

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13
Q

is friction a vertical or horizontal force

A

horizontal

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14
Q

friction occurs when

A

friction occurs when 2 or more bodies are in contact with one another

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15
Q

what are the 2 types of friction

A

sliding and static friction

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16
Q

what is static friction

A

Is the force exerted on one surface by another when there is no motion between the surfaces

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17
Q

apply static friction to a netballer

A

a netballer stationary prior to them using the floor to generate movement

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18
Q

what is Sliding friction def and exp

A

Sliding friction acts between two surfaces that are moving relative to one another.

a runner exerts and action force (internal) downwards and backwards in order to move forwards, and so friction acts opposite to this force (forwards), it acts in the same direction as motion (in this case)

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19
Q

apply sliding friction to a skier

A

the slippage is downhill and they are applying force forwards in order to go forwards as there is the additional gravity of going down a hill, and so friction acts opposite to that forward force and so friction acts backwards

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20
Q

what are the 3 factors that affect friction

A

surface characteristics
temperature
mass of object

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21
Q

how does surface characteristics affect friction inc eg

A

running spikes will increase friction of the runner and so will increase accel

ice is smooth and so has/could have “zero friction”

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22
Q

how does temperature influence friction inc eg

A

as temperature increases the amount of friction is reduced eg sweeping the ice in curling

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23
Q

how does mass affect friction

A

as the mass of the object increases, friction increases

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24
Q

what is air resistance

A

A force that acts in the opposite direction to the motion of a body travelling through the air

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25
Q

is air res a horizontal or vertical force

A

horizontal

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26
Q

what are the factors affecting air resistance

A

velocity of the moving object
mass
front cross sectional area
shape of the surface

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27
Q

how does velocity affect air resistance

A

more velocity=more air resistance

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28
Q

how does mass affect air resistance

A

less mass=more air resistance

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29
Q

how does front cross sectional area have an affect on air resistance

A

the greater the front cross sectional area the more air resistance there is

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30
Q

how does the shape of the surface affect the air resistance

A

a streamlined and smooth shape will create less air resistance

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31
Q

what is a net force

A

The resultant force acting on a body when all forces have been considered.

32
Q

what is a balanced force

A

Balanced force is when there are two or more forces acting on the body that are equal (inertia) stationary

33
Q

what is an unbalanced force

A

An unbalanced forces when a force acting in One Direction on a body is larger than a force acting in the opposite direction, movement will occur

34
Q

can there be a zero net force/balanced force eg

A

yes, when standing the weight force and the reaction force are equal in magnitude and in opposite directions and so there is zero net force and there is no change in motion

35
Q

is friction is equal to air resistance the net force is

A

zero

36
Q

is friction is bigger than air resistance the body will

A

accelerate

37
Q

is friction is smaller than air resistance the performer will

A

decelerate

38
Q

is displacement a vector or a scalar

A

vector

39
Q

is velocity a scalar or vector

A

vector

40
Q

is acceleration a scalar or vector

A

vector

41
Q

is weight a a scalar or vector

A

vector

42
Q

is momentum a scalar or vector

A

vector

43
Q

units for mass

A

kg

44
Q

units for displacement

A

m

45
Q

units for velocity

A

m/s

46
Q

units for acceleration

A

m/s^2

47
Q

units for weight

A

N

48
Q

units for momentum

A

kg m/s

49
Q

definition of mass

A

Physical quantity expressing the amount of matter or substance in a body from bone muscle fat tissue fluid

the quantity of matter a body possesses

50
Q

definition of weight

A

Downward force on a given mass due to gravity, external force, gravitational force that earth exerts on a body by pulling it down to the centre of the earth

51
Q

the greater the mass of the object the …… the weight …… them downwards

A

greater the weight
pulling them downwards

52
Q

is weight a vertical or horizontal force

A

vertical

53
Q

acceleration definition

A

Rate of change of velocity

54
Q

displacement definition

A

Length of a straight-line joining start and finishing points

55
Q

if the length of a race is 1.5km from start to finish in a straight line what is the displacement

A

1500m

56
Q

if a race is 40km in a loop what is the displacement

A

0m

57
Q

definition of velocity

A

The rate of change of displacement (how fast)

58
Q

momentum definition

A

Product of the mass and velocity of an object

59
Q

formula for weight

A

weight=mass x acceleration

60
Q

formula for acceleration

A

accel= change in velocity
time

61
Q

formula for velocity

A

velocity= displacement
time taken

62
Q

formula momentum

A

momentum=mass x velocity

63
Q

what is impulse (def)

define impulse(2)

A

amount of time a force is applied to an object/body

a measure of force applied over time, impulse = force x time (1)
measured in Newton seconds Ns (1)

64
Q

impulse can be manipulated to change …. or …..

A

momentum or velocity

65
Q

formula for impulse

A

impulse= force X time

(equates to change in momentum unless zero impulse

66
Q

what are the units for impulse

A

Newton seconds (Ns)

67
Q

is impulse a scalar or vector

A

vector

68
Q

is positive impulse acceleration or deceleration (and what does that look like on the graph

A

acceleration

it is in the positive force

69
Q

is negative impulse acceleration or deceleration (and what does that look like on the graph

A

deceleration

in the negative half of the graoh

70
Q

what are the units for the axis in an impulse graph

A

y is force in newtons
x is time in seconds or milliseconds

71
Q

on an impulse graph which comes first acceleration or deceleration and why

A

deceleration as it is the heel strike that causes negative impulse

link to newtons 3rd law

positive impulse represents front of the footfall

72
Q

if on an impulse graph the + and - are equal what does this mean overall

A

there is zero impulse as they are equal, they are moving at a constant speed, there is no change in momentum

73
Q

an impulse graph represents one…

A

footfall

74
Q

the acceleration that a performer achieves when sprinting or high jumping is related to impulse, what do you understand by the term impulse and how does the athletes use impulse during their sprint or take off (3)

A

impulse is force x time
it equates to the change in momentum
there is constant mass
impulse has direction
it represents a single footfall
+impulse for accel at take off
-impulse when foot lands
net impulse positive = accel
could draw an annotated graph

75
Q

what is the impulse like at different stages of a 100m sprint

A

at the start there is positive impulse
in the middle there is no impulse
at the end there is negative impulse

76
Q
A