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138063711 Kiss Notes Moving About Essay

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Preliminary Physics Topic 3

MOVING ABOUT
What is this topic about?
To keep it as simple as possible, (K.I.S.S.) this topic involves the study of: 1. SPEED and VELOCITY
2. FORCE and ACCELERATION
3. WORK and KINETIC ENERGY
4. MOMENTUM and IMPULSE
5. SAFETY DEVICES in VEHICLES

...all in the context of moving vehicles.

but first, let’s revise...
WHAT IS SPEED?

WHAT IS ENERGY?

“Speed” refers to how fast you are going.
You already know that mathematically:

Energy is what causes changes....
change in temperature (Heat energy)
change in speed (Kinetic energy)
change in height
(gravitational Potential energy)
change in chemical structure
(chemical P.E.)
...and so on.

SPEED = distance travelled
time taken
In this topic, you will extend your understanding
of speed to include VELOCITY, which is just a
special case of speed.

In this topic the most important energy form you
will study is the one associated with moving
vehicles...

WHAT IS FORCE?
A FORCE is a PUSH or a PULL.

KINETIC ENERGY

Some forces, like gravity and electric/magnetic
fields, can exert forces without actually
touching things. In this topic you will deal
mainly with CONTACT FORCES, which push or
pull objects by direct contact.

WHAT MAKES A CAR GO?
Overview
of Topic:

ENGINE provides ENERGY
(from chemical energy
in petrol)

Tyres PUSH on road...
FORCE acts...

FORCE causes

ACCELERATION
In the context of moving vehicles, the most
important force is FRICTION. Friction allows a
car’s tyres to grip the road to get moving, and
for the brakes to stop it again. Without friction
the car couldn’t get going, and couldn’t stop if it
did!
Preliminary Physics Topic 3 “Moving About”
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FORCE acts over
a distance...
“WORK” done

KINETIC
ENERGY
changes

VELOCITY
changes
1

MOMENTUM
changes

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CONCEPT DIAGRAM (“Mind Map”) OF TOPIC
Some students find that memorising the OUTLINE of a topic helps them learn and remember the concepts and important facts. As you proceed through the topic, come back to this page regularly to see how each bit fits the whole. At the end of the notes you will find a blank version of this “Mind Map” to practise on.

Average &
Instantaneous
Speed

Motion
Graphs
Forces
Vectors & Scalars.
Speed & Velocity

Adding
Vectors

Acceleration

Mass
&
Weight

Measuring
Motion

Speed
&
Velocity

Force
&
Acceleration

Newton’s
2nd Law

Centripetal
Force

MOVING
ABOUT

Work
&
Kinetic Energy
Energy
Transformations

Safety Devices
in
Vehicles

Momentum
&
Impulse

Equivalence of
Work & Energy
Law of
Conservation
of Energy
Momentum

Physics of
Safety
Devices

Inertia
&
Newton’s
1st Law

Preliminary Physics Topic 3 “Moving About”
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Newton’s
3rd Law

Impulse
of a Force

Conservation
of Momentum
in Collisions
2

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1. SPEED & VELOCITY
Average Speed for a Journey
If you travelled by car a distance of 300 km in exactly 4 hours, then your “average speed” was: average speed

=

distance travelled
time taken

=

300
4

=

75 km/hr (km.hr-1)

However, this does not mean that you actually travelled at a speed of 75 km/hr the whole way. You probably went faster at times, slower at other times,
and may have stopped for a rest at some point.

Distance-Time Graphs

Speed-Time Graphs

Perhaps your journey was similar to this graph.

The same journey could also be represented by
a different graph, showing the SPEED at
different times:

Start at the bottom-left of the graph and consider
each section A, B, C and D.

100

These graphs
represent the
same journey

A

0

1

2
3
TIME (hours)

4

1

Stopped.
Speed scale
reads zero.
2
TIME (hr)

3

4

This graph is very unrealistic in one way. It
shows the speed changing INSTANTLY from
(say) 100 km/hr to zero (stopped), without any
time to slow down. It also shows the car
travelling at exactly 100 km/hr for an hour at a
time... very unlikely with hills, curves, traffic etc.

This raises the idea of INSTANTANEOUS
SPEED: the speed at a particular instant of time.
The speedometer in your car gives you a
moment-by-moment reading of your current
speed... this is your instantaneous speed.

Changes of speed (ACCELERATION) will be
dealt with in the next section. For now we’re
Keeping It Simple!

On the graph, the GRADIENT at any given point
is equal to INSTANTANEOUS SPEED.

SPEED-TIME GRAPHS
show the SPEED of a moving object
at each TIME.

DISTANCE-TIME GRAPHS
show the DISTANCE (from the starting point)
at each TIME.
The GRADIENT at any point equals
INSTANTANEOUS SPEED.

The speed at any time can be read from
the vertical scale of the graph.
A horizontal section means that
the object was moving at constant speed.

A horizontal section means that
the object was not moving
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B
0

So although the average speed for the entire
journey was 75km/hr, in fact you never actually
moved at that speed.

“Flat” parts
DO NOT
mean
stopped,
but mean
constant
speed

C

20

gradient = zero
i.e. stopped

SPEED (km/hr)
40
60
80

300

C
B

D

A

0

Graph section A
Travelled 100 km
in 1.0 hour:
Speed =100 km/hr

You must not confuse the 2 types of graph and
how to interpret them.
D

50

Graph section B
Zero distance
moved in 0.5 hr:
Speed= zero.

gradient = distance
time
= speed

0

Graph section C
Travelled 50 km
in 1.0 hr:
Speed=50 km/hr

Study this graph carefully and compared it with
the other...

Distance-T
Time Graph

DISTANCE TRAVELLED (km)
100
150
200
250

Graph section D
Travelled 150km
in 1.5 hr:
Speed = 100 km/hr

3

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Scalars & Vectors
A Scalar quantity is something that has a size
(magnitude) but no particular direction.
A Vector quantity has both size (magnitude) AND
DIRECTION.

BUT, consider the “NET journey”: at the end of
the journey you end up 30 km EAST of the
starting point. So, your final displacement is “30
km east”.

So far we have dealt with only distances &
speeds... these are Scalar quantities, since they
do not have any special direction associated.

The VECTOR journey was:
• travelled 30 km east displacement in 1.5 hours.
• average velocity = 30/1.5 = 20 km/hr east.

Now you must learn the vector equivalents:
“Displacement” = distance in a given direction,
and
“Velocity” = speed in a given direction.

Notice that both displacement and velocity have
a direction (“east”) specified....
they are
VECTORS!
To make better sense (mathematically) of the
journey, the directions east & west could have
(+) or ( - ) signs attached. Let east be (+) and
west be ( - ).
Then the total
Average = Displacement
journey
Velocity
time
displacement was

Consider this journey:
drove 60 km EAST in 1 hour
START
then
drove 30 km WEST
in 0.5 hour.

(+60) + (-30) = +30 km.

Vav = S
t

As a SCALAR journey:
• travelled a total 90 km distance in 1.5 hours,
• average speed = 90/1.5 = 60 km/hr

Note: The symbol “S” is used for Displacement

MORE GRAPHS... Displacement - Time

...and the corresponding Velocity - Time Graph:
100

Refer to the previous Distance-Time graph.
What if the 300km journey had been 150 km north
(sections A, B, C) then 150 km south (section D)?

Back at starting point.
(Displacement = 0 )
1

2
TIME (hours)

3

4

In vector terms; displacement north is positive (+)
displacement south is negative ( - )

In section D:
displacement = -150 km (south)

C

TIME (hrs)

B
1
Zero velocity:
means stopped

2

3

4

Negative value:
south-b
bound
velocity
D

The velocity values for each part of this graph
are equal to the gradients of the corresponding
parts of the Displacement - Time Graph.
Note: Since the journey ends back
at the starting point,
total displacement = zero
and average velocity = zero
for the whole trip.

velocity = displacement
time
= -150 /1.5
= -100 km/hr (i.e. 100km/hr southward)
Preliminary Physics Topic 3 “Moving About”
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0
-1
100

0

south
-5
50

po
sit
ive
Gr
ad
ien
t

D

ve
ati
neg

Displacement NORTH (km)
0
50
100

nt
die
Gra

B

Velocity (km/hr)

150

Downsloping
line means
travelling
SOUTH

C

A

north
50

The Displacement - Time Graph would be:

Positive values mean
north-b
bound velocity

A

However, this simply points out how little
information the “average” gives you.
The instant-by-instant Physics of the
journey is in the graph details.
4

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Measuring Motion

Prac Work:
You will probably experience one or more of these commonly used ways to measure motion in the laboratory.

You might do some measurements as
suggested by this diagram
Time to travel from A to B measured by stopwatch

Distance between landmarks measured with sports tape

Landmark
A

Tape Measure & Stopwatch
The simplest method of all: measure the distance
or displacement involved, and the time taken.
Then use
speed (velocity) = distance (displacement)
time
Typical Results
Distance
Time
Velocity
(m)
(s)
(ms-1)
Car
Bicycle

87
87

6.2
22.4

Landmark B

The “Ticker-Timer”
Every time the hammer hits the
moving strip of paper
it leaves a dot.
The string of dots can be
analysed to study the
motion of the trolley.

Moving lab. trolley
drags a strip of
paper behind it

“Ticker-ttimer” device has a small hammer
which vibrates up and down every 0.02 sec.

14.0
3.9

However, this can only give you the AVERAGE
speed or velocity. In Physics we often need to
consider INSTANTANEOUS velocity.

Although this method is very out-dated, it is
still commonly used as a way for
students to learn how to measure
instantaneous velocity.
A moving object drags a paper strip on
which dots get printed (usually every 0.02
second) as it goes. The gap between dots is
a record of displacement and time. This
allows you to calculate the velocity over
every 0.02 s. It’s still an average, but over
such small time intervals it approximates
the instantaneous velocity.

Electronic or Computer Timing
You may use devices that use either “Light
Gates” or “SONAR” to record displacements
and times for you.
Once again, any velocities calculated are
averages, but the time intervals are so short
(e.g. as small as 0.001 s) that the velocity
calculated is essentially instantaneous.
Moving trolley equipped with a
sonar reflector.
(An aluminium pie dish will do)

Sonar “transponder” gives out
pulses of ultra-s
sound and picks
up any returning echoes

To computer for
analysis

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Worksheet 1

Speed & Velocity

Fill in the blank spaces.

Student Name...........................................
On a displacement-time graph, movement south
would
result
in
the
graph
sloping
m)................................... to the right and having a negative n)............................................

The average speed of a moving object is equal
to the a)............................ travelled, divided by
b)....................... taken. On a Distance-Time
graph, the c)........................ of the graph is equal
to speed. A horizontal graph means
d)................................. ...............................

The
vector
equivalent
of
speed
is
o).................................... The average velocity is equal to p)............................... divided by
q)....................... Instantaneous velocity refers to
r)..................................................................

On a Speed-Time graph, constant speed is
shown by e).......................................... on the graph. This does NOT mean stopped, unless the
graph section is lined up with f).............................

Laboratory methods for measuring motion
include using a tape measure and stopwatch.
This allows calculation of s)....................
............................ only. “Ticker-timers” record both t)............................... and .......................... on a paper tape. Average velocity can be calculated
for short time intervals which are approximately
equal to u)............................................ velocity. • Electronic or Computer-based devices often
use v)........................ or ......................................... to gather displacement, time and velocity data at
very short time intervals.

Speed and distance are both g).............................. quantities, because the direction doesn’t matter.
Often in Physics we deal with h)............................ quantities, which have both i)............................... and .......................................
The vector equivalent of distance is called
j)................................., and refers to distance in a particular k).............................. For example, if
displacement was being measured in the north
direction, then a distance southward would be
considered as l).............................. displacement.

Worksheet 2
Motion Graphs

Practice Problems
Student Name...........................................

A car travelled 200 km north in 3.0 hours, then
stopped for 1.0 hr, and finally travelled south 100
km in 1.0 hr.
1. What was the total distance travelled?

7. Use your graph to find:
i) average velocity for the first 3 hours.

ii) velocity during the 4th hour.
2. What was the total displacement?
iii) velocity during the last hour.
3. What was the total time for the whole journey?
4. Calculate the average
speed for the whole journey.

North

100

8. Construct a Velocity- Time Graph for this trip.

Time (hr)

0

Velocity (km/hr)

1

2

3

4

5

-1
100

South

-5
50

Displacement

6. Construct a
Displacement - Time
Graph for this trip.

50

5. Calculate the average velocity for the whole
journey.

TIME
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Worksheet 3
Practice Problems
Motion Graphs & Calculations
800

1. An aircraft took
off from town P and
flew due north to
town Q where it
stopped to re-fuel. It
then flew due south
to town R.

UNITS OF MEASUREMENT
So far all examples have used the familiar
km/hr for speed or velocity. The correct S.I.
units are metres per second (ms-1). You need
to be able to work in both, and convert from
one to the other.....
here’s how:
1 km/hr = 1,000 metres/hr
= 1,000m/(60x60) seconds
= 1,000/3,600 m/s
= 1/3.6
So, to convert km/hr
ms-1 divide by 3.6
to convert ms-1
km/hr multiply by 3.6

200

400

600

Displacement north (km)

Q

P

Time
(hr)
1

2

3

4

5

-4
400 -2
200

The trip is
summarised by the
graph.

Student Name...........................................

6

R

a) How far is it from towns P to Q?

2. A car is travelling at 100 km/hr.
a) What is this in ms-1?

b) How long did the flight P to Q take?
c) Calculate the average velocity for the flight
from P to Q (include direction)

b) The driver has a “micro-sleep” for 5.00 s. How far
will the car travel in this time?
c) At this velocity, how long does it take (in seconds)
to travel 1.00km (1,000m)?

d) What is the value of the gradient of the
graph from t=3 hr, to t=6 hr.?

3.
For this question consider north as (+), south as ( - ).

e) What part of the journey does this
represent?

A truck is travelling at a velocity of +20.5 ms-1 as it
passes a car travelling at -24.5 ms-1.

f) Where is town R located compared to town P?
a) What are these velocities in km/hr? (including
directions?)

g) What was the aircraft’s position and velocity
(including direction) at t=5 hr?

b) What is the displacement (in m) of each vehicle in
30.0 s?

h) What was the:
i) total distance
c) How long would it take each vehicle to travel
100 m?

ii) average speed
iii) total displacement

4. Where does this aircraft end up in relation to its
starting point?

iv) average velocity
(for the entire 6 hr journey)

Next, flew east at 105 ms-1 for 50.0 minutes.

100

200

Velocity (km/hr)
North

Next, flew west for 3.25 hours at 325 km/hr.
Time (hr)

0

i) Construct a
Velocity- Time
Graph for
the flight.

300

400

Flight details:
First flew west for 2.50 hr at 460 km/hr.

2

3

4

5

6

Finally flew east for 5.50 hours at velocity 125 ms-1.

-3
300

South

-1
100

1

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2. FORCE & ACCELERATION
Graphs of Accelerating Vehicles

Change of Velocity = Acceleration

You may have done laboratory work to study the
motion of an accelerating trolley. If you used a
“Ticker-timer”, the paper tape records would
look something like this:

Any change in velocity is an acceleration.
Mathematically,
acceleration = velocity change = final vel. - initial velocity time taken
time taken

Tape of trolley accelerating... dots get further apart

v = final velocity
u = initial velocity
t = time involved

Trolley decelerating (negative acceleration)... dots get closer

Units: if velocities are in ms-1, and time in
seconds, then acceleration is measured in
metres/sec/sec (ms-2).

The graphs that result from acceleration are as
follows:

Explanation: Imagine a car that accelerates at 1 ms-2:
1 sec. later
v = 1 ms-1

1 sec.later
v=2 ms-1

Remember,
Gradient
equals
Velocity

1sec.later
v=3ms-1

Displacement

Every second, its velocity increases by 1 ms-1.
Therefore, the rate at which velocity is changing
is 1 ms-1 per second, or simply 1 ms-2.
Acceleration is a vector, so direction counts.

+
ACCELERATION
VECTOR

VELOCITY
VECTOR

DISPLACEMENT-T
TIME GRAPH
Gradients decreasing
(curve flattens out)

THIS CAR IS SLOWING
DOWN... DECELERATING

ing
rat
ele
c
De

Gradient constant
(straight line)

Gradients increasing
(curve gets steeper)

Time

“Deceleration” (or negative acceleration) simply
means that the direction of acceleration is
opposite to the current motion... the vehicle will
slow down rather than speed up.

VELOCITY-T
TIME GRAPH
Constant
Velocity

A motorcycle travelling at 10.0 ms-1, accelerated
for 5.00s to a final velocity of 30.0 ms-1. What was
its acceleration rate?

Velocity
increasing

Solution: a = v - u = 30.0-10.0/5.00 = 20.0/5.00
t
= 4.00 ms-2.

A common error is to
think that this means the
object is moving
backwards. Wrong! It is
moving forward, but
slowing down.

g
in
at
ler
ce
De

Velocity

Example Problem 1

Ac
ce
ler
at
in
g

Start
v =0

Co
Ve nsta
loc nt
ity

a=v-u
t

Δ (Greek letter “delta”) refers
to a change in a quantity

Ac
ce
le
ra
tin
g

a = Δv
Δt

Tape of trolley moving at constant velocity (for comparison)

Velocity
decreasing

Velocity = 0
∴ Stopped!

Example Problem 2

A car moving at 25.0 ms-1 applied its brakes
producing an acceleration of -1.50 ms-2
(i.e. deceleration) lasting for 12.0 s.
What was its final velocity?
Solution: a = v - u,
t

Time
Gradient positive

so v = u + at
= 25.0 + (-1.50) x 12.0
= 25.0 - 18.0
= 7.00 ms-1.

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Gradient negative

On a Velocity-T
Time Graph
Gradient = Acceleration

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Force Causes Acceleration

PRESSING ON THE ACCELERATOR...

A simple definition of “Force” is a push or a pull.
However, in the context of moving vehicles,

Weight

Vertical forces are
balanced, and cancel

Force is what causes
velocity to change.

Thrust Force
Increased

Note that a change of velocity could mean:
• speeding up
• slowing down
• changing direction (velocity is a vector)

Friction &
Air Resistance
small forces

Horizontal forces
UNBALANCED

Reaction
Force

To actually result in a change of velocity, the
force must be
External

and

For example, if you were
inside a moving car and
kicked the dashboard,
this force would have NO
EFFECT on the car’s
motion...
This is an “Internal Force”
and cannot cause
acceleration.

TURNING THE STEERING WHEEL...

Unbalanced (Net) Force

Vertical forces are
balanced, and cancel

Forward & Back
Forces are balanced
and cancel
WEIGHT FORCE
Car pushes on Earth

(Thrust Force from
Engine is equal to
Friction forces)
Sideways
Forces become
UNBALANCED
(These would
be equal if
wheel not
turned)

Thrust
from
Engine

Friction
and Air
Resistance

This car will
SPEED UP

REACTION FORCE
Earth pushes back

This car will turn a corner
at constant speed
(but this is a changed velocity
since the direction changed)

BALANCED & UNBALANCED FORCES
GOING UP A HILL
(without increasing engine thrust)

The car above has a number of forces acting on
it, but they are BALANCED... those acting in the
same line are equal and opposite,
and cancel each other out.
This car will not alter its velocity or direction; it
will not accelerate. It is either travelling at a
constant velocity, or it is stationary.
EXAMPLES OF
BALANCED
UNBALANCED
FORCE
FORCES
SITUATION

Engine Thrust
still the same

Part of the
Weight Force acts
downhill to cancel
some of the thrust

Reaction Force is not
vertical, and no
longer cancels the
weight completely...
UNBALANCED FORCE

This bike will SLOW DOWN.
(Going down a hill, it will speed up)

PASSING OVER AN ICY PATCH ON THE ROAD
Opposite Forces are
BALANCED and cancel

Friction
still the
same

Weight (still vertical)

Weight

PRESSING ON THE BRAKES...
Virtually no
Thrust Force
because tyres
can’t grip on ice
This car will continue
in a straight line, at a
constant velocity...
whether the driver
wants to or not...

Vertical forces are
balanced, and cancel

Virtually
no Friction
on Ice

Weight

Thrust Force
decreases as

Friction
Increases as
Brakes are
applied

accelerator is
released

Reaction Force
cancels Weight
Car is out of control;
Can’t stop...
Can’t turn...

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Keywords

+1 +10 +100 +15 +2 +20 +20.5 +200 +30 +300 +400 +450 +5 +500 +575 +6.10 +60 +7 -0 -0.45 -1 -1.11 -1.18 -1.50 -1.82 -10 -10.0 -100 -11 -12 -12.52 -14.0 -150 -165 -1727 -2 -2.60 -2.76 -200 -22 -22.5 -24.5 -25.0 -3 -3.32 -3.41 -30 -300 -4 -4.00 -4.20 -4.4 -40 -420 -450 -5 -5.00 -50.0 -6.38 -6.82 -7.00 -70 -700 -735 -8 -88.2 -900 /0.750 /1 /1.33 /1.5 /1.75 /2 /2.5 /3 /3.6 /3.85 /4.50 /5.0 /5.00 /700 /750 /8.20 /a /m /t /v 0 0.001 0.02 0.1428 0.15 0.2 0.200 0.25 0.250 0.350 0.36 0.5 0.500 0.7 0.75 0.750 000 000/1 000/25 000/250 000/27.8 000/3 000/750 000/8.25 000/800 000j 000kg 000kgms 000m 000n 000x 000x1.7 000x10 000x252/18 000x502/70 000x83.32/500 01.energy 02 02.forces 03.matter 04.mixtures 05.elements 056 056km 06.cells 07.life 08.lifesystems 09.astronomy 1 1.0 1.00 1.05 1.08 1.1 1.10 1.15 1.19 1.2 1.25 1.3 1.32 1.33 1.4 1.40 1.43 1.5 1.50 1.59 1.7 1.70 1.73 1.75 1.8 1.80 1.82 1.83 1.9 1.93 1/3.6 10 10.0 10.5 10.6 10.earth 100 100/150 100/20.5 100/200 100/24.5 100/3.6 100/5 1002 100kg 100km 100km/hr 100m 100n 100v 102 105 105j 105x 1067 10ms 10n 10s 11 11.ecosystems 117o 1190n 12 12.0 12.5 12.waves 120 1200n 120kg 120n 120x5.25 1240ns 125 125/8.75 1250 125x 13 13.3 13.9 13.motion 1300 133 138063711 139m 13s 14 14.0 14.1 14.8 14.9 14.electricity 140 140/3.6 140km/hr 143o 144o 146o 14ms 15 15.0 15.3 15.atoms 150 1500 1502 150km 150ms 150n 150x60 15kg 16 16.reactions 160 160kj 1642 166ms 17 17.dna 18 18.0 18.evolution 180/3.00 180kg 180km 180x35.0 19 19.0 19.health 1kg 1ms 1n 1sec.later 1st 2 2.0 2.00 2.03 2.15 2.20 2.23 2.25 2.3 2.4 2.48 2.5 2.50 2.65 2.74 2.90 20 20.0 20.5 20.universe 20/200 200 200/150 200/3 200/900 2000 2002 2005 2009 200g 200kg 200km 200ms 200n 200x75.0 201 201ms 202 20km/hr 20ms 20n 20o 20x3.6 20x4.0 21 21.earthscience 210m 218.18 22 22.0 22.2 22.4 22.5 22.resources 224 225 23 23.0 24 24.5 240/32.5 2444 248 25 25.0 25.02 25/40 250 250/3.00 250/500 250g 250kg 250km 250km/hr 250m 250n 252 252km/hr 2575 25ms 25n 26 26.5 27 27.0 27.8 27o 28 28.24 29 2m 2ms 2n 2nd 2v 2x 2x160 2xek/m 3 3.0 3.00 3.03 3.04 3.2 3.20 3.25 3.3 3.44 3.50 3.52 3.6 3.64 3.85 3.852 3.9 3.91 3/4 30 30.0 30.02 30/1.5 30/10 30/20 300 300/3.6 300/5 300/6 300kg 300km 300km/hr 300x2.90 300x3.50 302 304 30ms 30n 30s 30x50 31 315 315km 32 32.0 32.5 325 325x3.25 326o 32n 32o 33 33.0 33ms 34 34.72 342o 34o 35 35.0 354o 359kg 359x9.81 35m 36 36.0 36n 37 375 38 38.2 38.9 380/19.0 380ns 39 390.6 391kg 3ms 3rd 4 4.0 4.00 4.08 4.16 4.24 4.35 4.5 4.50 4.80 4.88 40 400 400kg 400km/hr 400x 400x1.50 402 406 40m 40n 412n 42.385 431 4333 450 450kg 450n 450x 460 460x2.50 47.9 475 475km 47n 480kg 480x22.5 4th 4x 5 5.0 5.00 5.02 5.20 5.25 5.252 5.3 5.50 5.7 50 50.0 500 500.va 500/3 500/6 500g 500kg 500km 500m 500n 500va 500x 500x0 500x20.0 500x20.02 500x22.02/25.0 500x32.0 500x4 500xv2 50km/hr 50m 50ms 50n 50x4.5 50x60 522 53o 54 54o 557 56o 590 5hr 5n 5th 6 6.0 6.00 6.2 6.20 6.25 6.30 6.31 6.38 6.51 60 600 600/1.5 600kg 600km 600x 600x15.0 600x2.65 600x27.0 60kg 60km/hr 60x60 615m 62 625 630kg 630kgms 630x10.0 650/100 650ns 6583 67 69.6 6o 7 7.00 7.2 7.29 7.71 7.85 70/5.0 700 700gram 700kg 700n 700x 700x24.5 700x8.50 70m 70m/s 70ms 70o 70x3 70x3.6 714n 725 727n 72km/hr 72o 73.8 735m 75 75.0 750 750/1250 750g 750kg 750v2 750x 750x0 750x10.0 750x15.0 75kg 75km/hr 7n 8 8.0 8.00 8.10 8.20 8.25 8.5 8.50 8.502 8.75 80 80.0 800 800kg 800n 800x9.81 80kg 80ns 810 815 820 820kg 825 825/50.0 83.3 840 848 850 850kg 850ms 850x2.15 87 9 9.0 9.00 9.25 9.68 9.81 90 90.0 90/1.5 90/3.6 900 900kg 900n 900x22.5 900x35.0 900x6.25 92 9467 950 994 9x103ns a2 a4 aa ab abl abn abrupt absorb ac acceler accid accident accord account accur achiev acid act action actual ad add addit advis ae af affect ag agenc agreement ah ahead ai air airbag aircraft aj ak al alien allow almost alon along alreadi also alter although aluminium alway amount analys analysi and/or angl anim anoth answer anyth apart appar appear appli appropri approx approxim area arithmet around arrow assign associ assum 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everi everyday everyth evolut exact exampl exceed exert exhaust exist expect experi experiment explain explan explos extend extern extra extra-terrestri f f.s f.t f/a f/m f2 facilit fact factor fail fall familiar far fast faster fax fc fcr featur feel ff fi field figur file filenam fill final find fire first fit fix flat flatten flew fli flight flow flung follow forc force/acceleration form format formula forward found four fraction frame free frequent friction friction/retarding front fuel full fulli g gain gap gas gase gate gather gearbox general generat genet gentler get give given go goe gone govern gr gra gradient gradual grand grand-sound graph gravit graviti great greek grid grip ground gun h halt hammer hand hang happen he/she/it head head-on head-to-tail headon health heat height help henc high higher hill hint his/her/its hit hold home horizont hour howev hr hrs hsc human hump i.e i/f i/t ice ici idea ident ie ien ignor ii iii illeg imagin imaginari immedi immens immov impact impal implement import imposs impuls inc incid includ increas indic industri ineffici inelast inertia inflat inform ing initi injuri insid instal instant instant-by-inst instantan institut insuffici inter inter-c intern interpret interv intiti introduc invers involv isaac issu iti iv ive j join jolt joul journey jump jupit k k.i.s.s kcic ke keep kept key kg kg.ms kgms kick kick-b kill kilogram kilogram-m kinet kiss kj km km.hr km/hr know known l lab lab.trolley label laboratori lac laden land landmark lap larg larger last later launch law le learn least leav left leg ler less let lethal letter level li licenc life lift light like limit line link liquid list littl live loc local locat lock logo long longer look loos lose loss lost lot love low lower lta m m/s ma ma.s ma.ua ma.va macquari magnitud [email protected] main maintain make mani map mark mass massiv master materi math mathemat matter max max15.0 max6.25 maximis maximum may mb mb.ub mb.vb mean meant meanwhil measur memoris metal method metr metre/sec metres/hr metres/sec/sec mg micro micro-sleep microsoft might mind mini mini-van minimis minor minut miss mitchel mixtur mngment modern moment moment-by-mo momentum money moon most motion motionless motor motorbik motorcycl move movement ms mu mu2 much multipl multipli must mv mv2 mv2/f mv2/r mxv n n.m n.s name natur near need neg negat negatv neglibl negoti net network never new newton newton- newton-metr newton-second next nm non non-profit nonprofit north north-b north-south northbound northward note noth notic nsta nsw nt number numer o obey object observ obtain obvious occup occur often on-screen one opp/adj oppos opposit option orbit orient origin out-dat outlin overcom overhead overview p p.e pack page paper part particip particl particular paseng pass passeng patch path pattern pdf pedal peopl per perhap period perman permit person petrol photo photocopi physic pick pie plane planet plant pleas po point port portrait portrait-orient posit possess possibl potenti power powerpoint prac practic practis precis preliminari press pressed-b prevent previous principl print probabl problem proceed produc product profit project projector proof proof-read properti proport propuls prove provid pull puls push pythagorus q q3 q8 quadrupl quanta quantiti quark quarter question quit r r2 ra race racer radius rais rapid rare rat rate rather ratio re re-bound re-fuel reach react reaction read readi real real-lif realiti realli rear rear-end recognis recoil record rectangular reduc refer reflector regular relat relationship releas remain rememb repeat repres reproduct requir res residenti resist resloc resourc respect respons rest restrain result retard retriev retro return revers revis rho rider right right-angl risk road rock rocket role rope rotat rough round rule runway s.i s/t s/v safeti said sail salli say scalar scale school scienc screen search seat seatbelt sec sec.later second section see seek seem sens separ set sever ship shipwreck short show 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touch tow tow-bar tow-cabl toward town trademark traffic tragic train tranfer transform transpond travel tri trial triangl tricki trigger trigonometri trip trolley truck true truli ttimer turn twice two type typic tyre u u2 ua ub ul ulta ultim ultra ultra- unbalanc underneath understand undertstand unfortun unit univers unknown unless unlik unlimit unrealist unrestrain upon upward us usag use usual util v v-u v.t v2 va valu van various vav vb ve vecto vector vector/scalar vehicl vel veloc velocity-t velocity-tim verifi version vertic via vibrat view virtual visual visualis w w/f w/g w/s walk wall want water wave way wear weigh weight well went west west-b westward wet wheel whenev wherea wherev whether white whoa whole wind windscreen wing wire within without work worksheet world worn would wreck wreckag wrong www.keepitsimplescience.com.au x x0.15 x1.50 x1.5x3.2 x10 x10-1n x10.0 x100 x102 x102kg x102kgms x102n x103 x103/0.200 x103/0.350 x103/1 x103/10 x103/15.3 x103/3.20 x103/800 x103kg x103kgms x103n x103x x104 x104/10 x104/22.5 x104/359 x104/450 x104/750 x104j x104kgms x104n x104ns x105 x105/2.50 x105/22.2 x105j x105kgms x105n x106 x106/250 x106/8 x106j x20.0 x200x102 x200x302 x250x1662 x3.50 x3.6 x3.642 x30 x30.0 x4.50 x4.80 x5 x5.00 x5.20 x500x x500x10.02 x500x102 x500x302 x600x x600x15.02 x60x60 x900xv2 xma xv y year yes z zero zone δ δek δt δv δρ ρ ρf ρi σf φ