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Slide 1

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P2 Revision…read more

Slide 2

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Speed and Velocity
SPEED ­ how fast your going
VELOCITY ­ how fast you going and the direction
S S = Displacement measured in metres (m)
V = Velocity measured in m/s
T = Time measured in seconds (s)
A cat skulks 20 metres in 35 seconds
Find a) average speed b) how long it takes to skulk 75m
a)V = s/t = 20/35 = 0.5714 = 0.57m/s
b)T = s/v = 75/0.5714 = 131s = 2mins 11s…read more

Slide 3

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Acceleration is how quickly the velocity is changing
V = final velocity measured in m/s
U = initial velocity measured in m/s
A = acceleration measured in m/s²
A x T T = Time taken measured in seconds (s)
A skulking cat accelerated from 2m/s to 6m/s in 5.6s. Find its acceleration
A = (v-u)/t
(6-2)/5.6 = 4/5.6 = 0.71 m/s…read more

Slide 4

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Velocity Time Graphs
· Flat sections represent a steady speed
· Steeper the graph, the greater the acceleration/deceleration
· Uphill sections (/) are acceleration
· Downhill sections (\) are deceleration
· The area under any section of the graph = distance travelled in that time
· A curve means changing acceleration
· Acceleration = gradient = vertical change
horizontal change
· Velocity = read off the value from the velocity axis
· Distance travelled = in any time interval is equal to the area under the graph…read more

Slide 5

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Six different forces;
Gravity/Weight ­ always acting straight downwards
Reaction force from a surface ­ acting straight upwards
Thrust/Push/Pull due to an engine speeding up something
Drag/Air Resistance/Friction ­ slowing something down
Lift due to an aeroplane wing
Tension in a rope or cable
There are five different force diagrams;
1) STATIONARY OBJECT ­ All forces in balance
- Gravity/Weight is acting downwards
- Reaction Force pushing up
- So all forces are balanced
- Without reaction force it would accelerate
downwards due to the pull of gravity
- The 2 horizontal forces must be equal and opposite
(or zero) otherwise the object will accelerate sideways
Weight/Gravity…read more

Slide 6

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2) STEADY HORIZONTAL VELOCITY ­ All forces balanced
To move with
a steady
Drag speed the
forces must
be in balance.
Weight If there is an
3) STEADY VERTICAL VELOCITY ­ All forces balanced unbalanced
force then you
not a steady
Weight…read more

Slide 7

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Slide 8

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Slide 9

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Slide 10

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