# Motion

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Speed
How fast something is moving, regardless of direction
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Displacement
How far an object has travelled from its starting point in a given direction (s)
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Velocity
The rate of change of an object's displacement (its speed in a given direction) (v)
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Acceleration
The rate of change of an objects velocity (a)
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Uniform acceleration
Constant acceleration (suvat equations)
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Suvat equations
v = u + at s = ((u+v)/2) x t s = ut + 1/2at^2 v^2 = u^2 + 2as
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Freefall
the motion of an object undergoing an acceleration og 'g' ( only gravity and nothing else)
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what is g?
9.81ms-2
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How we calculate projectile motion
thinking of horizontal and vertical motion separately
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Horizontal motion is...
constant (speed = distance / time)
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vertical motion is...
affected by the acceleration due to gravity
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if something is projected at an angle
You start off with both horizontal and vertical velocity
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in Displacement-Time graphs: Acceleration is...
a curve (accelerating at a uniform rate means the rate of change of the gradient will be constant)
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in Displacement-Time graphs: Velocity is...
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in Displacement-Time graphs: instantaneous velocity in a curved graph
Tangent to the curve
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in Velocity-Time graphs: Acceleration is...
the gradient (change in velocity/time) (uniform acceleration is a straight line)
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in Velocity-Time graphs: y = mx + c
v = at + u
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in Velocity-Time graphs: Displacement is...
Area under graph (average speed x time)
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in Velocity-Time graphs: finding displacement from a curved graph
Estimate area
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Factors affecting motion
Angle, mass, shape and size, friction
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Stopping Distance =
Thinking Distance + Braking distance
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Reaction time
time body takes to react and hit brakes
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Thinking distance
distance vehicle travels in reaction time
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equation and affected by
speed x reaction time tiredness, alcohol/drugs, illness and distractions
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Braking distance
distance to stop after brakes
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depends on
braking force - reduced by reduced friction between the brakes and the wheels Friction - between tyres and road reduced by wet/icy roads, leaves/dirt or worn out treads Mass
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## Other cards in this set

### Card 2

#### Front

How far an object has travelled from its starting point in a given direction (s)

Displacement

### Card 3

#### Front

The rate of change of an object's displacement (its speed in a given direction) (v)

### Card 4

#### Front

The rate of change of an objects velocity (a)

### Card 5

#### Front

Constant acceleration (suvat equations)