Bab 5 sains spm ting. 5

8/11/2019 Bab 5 sains spm ting. 5

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Chapter 5

MOTION

Prepared by: En Shafie Bin Buyamin


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5.1: Analysing the Motion of Vehicles

on Land

Bicycle:

- Pedals turns crank

- Sprockets in chainwheels move chain

- Cog turns the rear wheel

- Bicycle moving forward

Vehicle Without Engine


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Crank

Pedal

Chain

Cog

Handlebar


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Front-mounted

Gasoline-burning engine

Front-wheel drive

Vehicle With Engine


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Vehicle with Engine


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Four-Stroke Petrol Engine

Piston move down

Intake valve open Draws in air and fuel

1. Intake stroke car


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Intake valve close Piston goes up

Compress fuel and air

Heat the mixture Spark plug ignites

2. Compression stroke


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Spark ignites fuel Fuel burns

Hot gases expand

Force piston downward

3. Power stroke


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Exhaust valve opens Piston rise

Push out waste through

exhaust valve

4. Exhaust stroke


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Car
http://www.proton.com/protonexora


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Four-Stroke Diesel Engine

Piston move down Intake valve open

Draws in air and fuel

1. Intake stroke

Larger vehicle: bus, truck


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Intake valve close Piston goes up

Compress air

Heat the air

2. Compression stroke


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Diesel forced intocylinder

Fuel burns without spark

3. Power stroke


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Exhaust valve opens Piston move up

Push out waste through

exhaust valve

4. Exhaust stroke


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Bus
http://upload.wikimedia.org/wikipedia/commons/0/0b/ACTION-bus-333.jpg


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Truck
http://upload.wikimedia.org/wikipedia/commons/7/74/Actros182201.jpg


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Two-Stroke Petrol Engine

Mixture of fuel and air compressed Spark plug ignite

Air and fuel burns

Explosion pushed piston downward

Compress air and fuel in crankcase

Piston at bottom, exhaust port exposed

Exhaust gases out

1. Upstroke

Lower-power application: motorcycles, lawn mower


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Piston at bottom, intake port exposed

Pressure of mixture in crankcase

Mixture rushes into cylinder

Piston back towards spark plug (compression

stroke) Vacuum in crankcase

Opens the reed valve: sucks in air and fuel fromcarburettor

Spark plug ignites again

Cycle repeated

2. Downstroke


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Motorcycle
http://upload.wikimedia.org/wikipedia/commons/3/36/1997SuzukiGS500E-001.jpg


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Lawn mowers
http://upload.wikimedia.org/wikipedia/commons/9/90/MTD_Lawn_Mower.jpg


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The relationship between the structure and operation of the

engine and the movement of vehicles

Cylinder block: Have pumps, pulleys,

cylinder cavities

Cylinder cavities which piston moves

Car have 2,3,5, 12 or 24 cylinder

More cylinder = more power


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Combustion of engine creating gas

Push piston up ad down

Creates engine power

Transferred to drive shaft of wheel

Via gear box

Car move


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5.2: Speed, Velocity and Acceleration

Speed (laju): - How fast an object moves

- No direction

Average speed = Distance (metre)

Time (second)= m/s

= ms-1


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Velocity (halaju):

Distance travelled in a given time in a particular direction

Velocity = Distance (metre)

Time (second)

= in particular direction

Example: Boy running at 4 m/s to the south


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Acceleration (Pecutan):

An object accelerates or decelerates where there

is a change of speed or velocity

Acceleration = Change in velocity (m/s)

Time taken (s)

Example: Final velocityinitial velocity

Time taken

= 903

= 9 = 3 m/s2

3


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Acceleration

Unit = meter per second per second (m/s2)

When acceleration negative= decelerates


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5.3 : Inertia

= Property of an object that resist anychange in its motion

Depend on weight- Heavy object harder to move / stop

Negative effect

- Injury like in car accidentPositive effect

- Activity like to hammer


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Application of inertia


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5.4 : Momentum

= Multiplication of an objects mass with its

velocity

Momentum = mass x velocity

Example: 2.5 kg toy car moving at velocity 4 m/s

Momentum = 2.5 kg x 4 m/s= 10 kgm/s

Momentum depend on mass & velocity

Greater the mass = greater momentum

Greater the velocity = greater momentum


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Conservation of Momentum

The law of conservation of momentum

Momentum depend on mass & velocity

Greater the mass = greater momentum

Greater the velocity = greater momentum

The total amount

of momentum

before collision

The total amount

of momentum

after collision=


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Momentum in daily lives

Example:

- Design cars that can absorb momentum

during collision

- Front and rear part easily crush

- Extend time of impact

- People in the car absorb less momentum


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Cars absorb momentum during collision
http://upload.wikimedia.org/wikipedia/commons/5/5b/Crashed_Honda_Accord.jpg


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5.5 : Pressure

Force exerted over a given area

Unit = N/m2

Example: force is 1200 N pushes on area of

4m2

1200 = 300 N/m2

4

Pressure = force (N)

area (m2)

P = F

A


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5.6: The Principles of Hydraulic System in

Everyday Life

Gases and liquids = fluids (bendalir)

Can change shape with container

Pressure inside acts outwards in alldirection


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Gas can be compressed


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Liquid cannot be compressed

- Pressure equally transmitted in all direction


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Pascals Principle

The principle of transmission of liquidsstates:

Pressure is transmitted equally in alldirections


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Hydraulic System

Total output force larger than input Larger size of surface output piston


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Lift heavy object


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Output column 100x of input column


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From Pascals principle

The input pressure = The output pressure

P input = P output

F input = F output

A input A output

Pressure X = Pressure Y , Pressure = Force

Area

Force X = Force Y

Area X Area Y

B A Y i 100 ti l th A X


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Because Area Y is 100 times larger than Area X,

Force X = Force Y

Area X 100 x Area X

Force Y = Force X

100 x Area X Area X

Force Y x (100 x Area X) = Force X x (100 x Area X)

100 x Area X Area X

Force Y = Force X x 100

Force Y = 100 Force X

10 N i t i t 1000 N f th t t l


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10 N on input piston = 1000 N force on the output column.

Can lift the car using hydraulic system.


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Tipper Lorry
http://upload.wikimedia.org/wikipedia/commons/e/e2/Ashok_Leyland_Tipper_Truck_726.jpg


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Excavator (Jengkaut)
http://upload.wikimedia.org/wikipedia/commons/9/91/Kettenbagger_CAT_325C_LN.jpeg


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5.7 : The Motion of Vehicles in Water

Upthrust : Force of water that pushes upward

V-shaped and curved boat raises the boat up, faster andreduce drag

Hydrofoil Hovercraft
http://rds.yahoo.com/_ylt=A0S020oCXklKl08AAO2jzbkF/SIG=128k19i88/EXP=1246408578/**http%3A//www.flickr.com/photos/8749230@N08/2248478853/


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Boat


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Submarine


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Archimedes Principle

The upthrust acting on an object is equal to

the weight of the fluid that object displaces

Application on ships and submarine


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Submarine

Float

sinks


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When ballast tank

Opened, Sea water

enters. Submarinebegins to sink

5 8 : Vehicle in the Air


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5.8 : Vehicle in the Air

1. Hot balloon / gas balloon: Hot air less dense,

float in air2. Aeroplane :

- Aerofoil ( air flow along wings, lift upward)

3. Jet engine: mixture of air and fuel burns. Push

forward

4. Helicopter: Blades spin, overcome weight and

lift

5. Rockets:- Combustion chamber (mix of fuel and

oxygen)

- Burnt and push upwards


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Jet


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Helicopter


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Rocket


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Rocket Engine


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Rockets and Jets Engines

Similarities

Principle of conservation of momentum

Hot gases pushed backward, vehicle

pushed forward


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Rockets and Jets Engines

Differences

Rockets Jet Engines

Carry oxygen Oxygen from air

Travel outer space Not outer space

Thrust by combustion of

fuel and liquid oxygen

Thrust by compressing

and pushing surrounding

air using turbines


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Aeroplane


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Glider

5 9: Appreciating the ability and creativity of mankind in


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5.9: Appreciating the ability and creativity of mankind in

inventing and designing vehicles

for the betterment of life

Practice good habits in handling vehicles

Practice caring attitudes when using public

transport system

Bab 5 sains spm ting. 5

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