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SECTION A 1. Water wave / thermometer

2. Water pressure / impulsive force3. Specific heat / heat release / kettle / logic4. Work done / potential energy5. Refraction, internal / mirage6. Parallel circuit, V = I x R / electromotive7. Transformer / Hooke’s laws 8. Half-life / determine volume of milk / smoke detector

9. Force and liquid10. Force and motion

SECTION B 9. Bernoulli’s principle / Inertia 10. Diodes, rectifier, LDR and LED / Interference of waves

SECTION C 11. Resistant length of wire / pressure mass

12. Light or water waves, diffraction, radar

1. electricity and electromagnetism

2. transistor try to understand the flow through the base and the affect to the

bulb, speaker or sensor on the output.

3. Radioactive may ask in structures questions on long structures part.

4. HEAT and Pressure especially density part and Achimedes.

5. Light lenses for essay.

electromotive force E= Ir + V and lenses 1/f = 1/u + 1/v forgraph

Planning experiment chapter of heat is popular this time, Charles

and Boyle’s law, maybe Q relate to temperature.

The chapter of Pressure regarding density P relate to density.

The resistance affect by the length of wire and area crosssectional of wire.

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Form 4 Chapter 1Introduction to Physics Understanding Basic Quantities and Derived Quantities

Prefix P1’06/07/08/09/10/12 (the shortest )

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Scalar and Vector

PHG’14

Measurement

1. Measurements are trials to determine the actual value of a physicalquantity.

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2. An error is an uncertainly in a measurement. There are two maintypes of errors.

3.a. Accuracy is the degree to which the measurement represents the

actual value.b. Ways to increase accuracy:

i. Repeat readings and calculate the average/mean valueii. Avoid parallax (by put a mirror under the scale of the

ammeter ) SPM P2S05 and zero errors. (able to detect smallerchange of current) SPM P2S06

iii. Use measuring instruments with higher accuracy.4.

a. Consistency is the ability to register the same reading when ameasurement is repeated.

b. Consistent but not accurate is the point are close each other but faraway from the target. SPM 08 A deviation is the difference betweenthe measured value the mean/average value. SPM 05

Low deviation => High consistency

c. Relative deviation is calculated to determine consistency.d. Ways to increase consistency:

i. Avoid parallax errorii. Use suitable measuring instruments for measurements

5. Sensitivity is the ability to respond to a small change in the quantitymeasured. SPM 07

6. Voltmeter – a. Physical quantity: Volt b. To measure potential differencec. Scale: 0.1V

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d. Do repeated reading of potential difference, v for each current. Howfor three times & find average value.

7. Rheostat – to control / change the current by varying the resistancein the circuit. SPM 06

Ammeter for connect series to a circuit

1. Physical quantity: Current SPM P2S05 2. Smaller division enables to detect a smaller change in current.

Therefore, more sensitive. Physical quantity: Current SPM P2S05 3. When reading, the eye must be in a position where pointer’s image is

right behind the pointer.

Vernier Callipers,

1. The accuracy of the Vernier Callipers is 0.01 cm.2. The outside and inside jaws are used to measure the external and

internal diameters respectively. The depth of an object is measuredusing the tail.

3. The smallest division of the main scale is 0.1 cm while the smallestdivision of the vernier scale is 0.01 cm.

4.a. To obtain a reading of the main scale, the '0' mark of the vernier

scale is used. In Figure 1.3, the '0' mark of the vernier scale lies between 4.4 cm

and 4.5cm. The reading of 4.4 cm is taken. SPM 11 b. The reading of the vernier scale is the mark which is in line with any

of the marks on the main scale. The number of marks on the vernierscale is multiplied by the accuracy of the vernier scale. In Figure 1.3,

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the reading of the vernier scale is:

6 0.01 cm = 0.06 cm

c. Therefore, the reading of the vernier callipers shown is the sum of thereadings of the main scale and the vernier scale.

4.4 cm + 0.06 cm = 4.46 cm

5. A pair of vernier callipers has both positive and negatives zero errors.

Micrometer Screw Gauge

1. The accuracy of the micrometer screw gauge is 0.01 mm.

2. When taking a measurement:a. The thimble is turned until the anvil and spindle grip the object tight.

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b. The ratchet knob is then turned until a 'click' sound is heard to ensurethat suitable pressure is exerted onto the object.

3. The reading on the micrometer screw gauge in Figure above can beobtained as follows: SPM 05

The reading on the main scale = 12.0 mm

The reading on the thimble scale = 45 0.01 mm = 0.45 mm

Micrometer screw gauge reading

= Main scale reading + Thimble scale reading

= 12.0 mm + 0.45 mm = 12.45 mm

4. The accuracy of the micrometer screw gauge is also affected by zeroerrors. Before using it, determine its zero errors, if any.

5. Precaution:a. Position of eye must perpendicular to the scale of the micrometer

screw gauge to avoid parallax errorb. Avoid over tightening the aluminum sheet by using the ratchet.

Thermometer SPM13 P2 PHG’14

1. A thermometer is used to measure the degree of

heat (definition temperature PHG’14, PP’14)2. There are two types of thermometers.a. Thermometers with a range of-10 °C to 110 °C and accuracy of

1 °C PHG’14

b. Thermometers with a range of 0 °C to 360 °C and accuracy of

2 °C.(more sensitive because the smallest division is smaller & abledefect smallest change)

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3. Liquid use: Mercury & opaque so easily to observe in the reading

4. When the temperature increases, the expansion in volume, kineticenergy increases.

5. Thin glass wall of bulb – more sensitive 6. Low freezing point – to prevent liquid freeze & high boiling point

– not easily boil

Experiment

1. To investigate the relationship between the length, L of a coil of wire

wound round a test tube and its number of turns SPM 10 P3 a. Manipulated: Number of turnsb. Responding: Length of coilc. Constant: Diameter of wire / thickness of wire / cross-sectional area

of wire

Scientific Investigation

Experiment

1. To investigate the relationship between the length, l of a simplependulum and the period of oscillation, T. SPM 08 P3

a. Manipulated: Length of pendulumb. Responding: Period of oscillationc. Constant: The gravitational acceleration / the mass of the bob /

number of oscillationd. Hypothesis: The length of pendulum increases, the period of

oscillation increases.

Form 4 Chapter 1Introduction to Physics Linear Motion

1. Distance (scalar quantity) is the total length of the path moved by anobject.

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2. Displacement (vector quantity) is the shortest distance between thefinal positions of an object to a reference point in a specifieddirection.P1’07/12 /[calculate], [area under thegraph] P1’11 KDH’14

3. Speed (scalar quantity) is defined as the rate of change of distancewith time. SPM P2S06/E07

PHG’14

4. Velocity (vector quantity) is defined as the rate of change ofdisplacement with time, unit metre per second ( ms

-2 ). SPM 08

KDH’14

5. Acceleration (vector quantity) is defined as the rate of change ofvelocity with time, SBP’14 unit ( ms

-2 ). SPM P2E07

SBP’14, KDH’14,

PHG’14

6. Modifications that can be made to make a man run faster andachieve maximum acceleration. SBP’14

i. Type of attire: light/tight/smooth (reason: less air friction)ii. Type of shoes: spike shoes/shoes with grooves (reason: better grip,

prevent slippery)

iii. Additional equipment: starting block (reason: increase forward forceat starting)7. An object is under going a deceleration when it is slowing down. The

rate of change of velocity of the object has a negative value.8. The ticker time can be used to measure the velocity and acceleration

of an object.9. The ticker timer uses an a.c. 50Hz power supply. Thereforea. Makes 50 ticks on the ticker tape in one second.b. Makes one tick in 0.02 second. PHG’14

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10.

11. An object which start to move with an initial velocity, u andattains a final velocity, v in time, t has an acceleration of SPM 08

-> Equation (1)

12.

Example 1:Time taken for an object to fall from a height from the moon’s surface islonger than the earth’s surface. Because g moon < g earth. SPM 05

13. For motion with constant acceleration:

-> Equation (2)

-> Equation (3)

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15. Motion graphs. Displacement-time graphs

a. Velocity-time graphs P1’05/07/08/09/10/12

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Inertia

1. Inertia is the natural characteristic of an object that resists changes

to its state of motion.2. Newton's first law of motion states that:

Every object continues in its state of rest or uniform speed in a straight line

unless acted upon by an external force. SPM 11

3. Newton’s third law of motion: Action and reaction; they are alwaysof same magnitude but in opposite directions. SPM 08

4. Inertia is a phenomenon and it has no unit.

5. The table below shows a few situations involving inertia.

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Relationship between Mass and Inertia

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1. It is more difficult to start a swing that carries a person in motioncompared to a vacant swing.

o When the total mass of the swing is larger, the resistance to changeits initial position is greater. Hence, when the mass increases, the

inertia increases.2. Similarly, it is more difficult to stop a moving swing that carries aperson compared to a vacant swing because when the total massis larger, the resistance to change its initial movement isgreater . SPM 06 P3

EXPERIMENT SPM 06 P3 SPM 13 P PHG’14

Aim : To investigate the relationship between mass and inertia using an inertia

balance

Situation : A shopper in a supermarket observes that it is always easier to start andto stop an empty trolley than a full trolley.

Problem : What is the relationship between mass and inertia?

Inference : The mass of an object affects its inertia.

Hypothesis : The larger the mass, the larger its inertia (represented by a longer period

of oscillation)

Variables :

a. Manipulated: Mass of plasticine, m

b. Responding : Period of oscillation, T c. Fixed : The distance between the plasticine and the G-clamp and the

stiffness of the hacksaw blade

Apparatus/MaterialsHacksaw blade, plasticine balls, G-clamp and stopwatch.Arrangement of Apparatus

Procedure

a. The apparatus as shown is prepared.b. A 0.05 kg plasticine ball is fixed to one end of the hacksaw blade

while the other end of the hacksaw blade is clamped to the leg of atable.

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c. The free end of the hacksaw blade is displaced horizontally to oneside of the table and released so that it oscillates.

d. The time for 10 complete oscillations, t , is measured using astopwatch and this step is repeated to obtain the time for 10

oscillations for the second time, t The average value of t and t iscalculated as t. The oscillation period, T is determined by using T=

t ⁄ 10. KDH’14

e. Steps 1, 2 and 3 are repeated using plasticine balls with masses 0.10kg, 0.15 kg and 0.20 kg.

Results

Table 2.3

Data Analysis

Discussion

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1. Both the graphs show that the oscillation period increases with massof plasticine.

2. The formula that relates T2 and m is T

2 = 4π(

t ⁄ 10 ) where k is the

stiffness of the hacksaw blade and T2 is directly proportional to m.

ConclusionWhen the mass of an object is larger, the inertia is also larger. Thehypothesis is accepted.

Ways to reduce the negative Effect of Inertia

2. Safety Measures in Vehicle to Reduce Negative Effect ofInertia

i. Seat belts – to prevent the drivers / passengers from the being

thrown forwar . o increases sloping timeo reduce impulsive forceo stop the motion of driver

ii. Air bags – prevent the driver/passenger from being injured of hittingthe dashboard.

3. Other Safety Measure

i. Steering column – Easily collapsed during accident to prevent it

from injuring the driver.ii. Head rests – Prevent the head of the passengers from being thrown

backwards.iii. Centre of Gravity is lowered to increase the stability.iv. Screens – Only crack into small pieces and not sharpv. Engine – Collapse downward during collision.vi. Reinforced body structure – to protect the passengers / driver.vii. Speed and passengers limits – to reduce the momentumviii. The front & rear sections of a car designed to crumple

easily SPM 07 – To increase impact timeix. Crumple zone SPM 10 – is crushed & compressed when an

obstacle to lengthen collision timex. Bumper filled with shock absorbers – to minimises the impulsive

force during an incident .

4. Lorries or trucks that carry heavy loads utilise the followingfeatures to reduce the negative effects of inertia:

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Momentum

1. A fast moving trolley has a higher resistance to a change in its stateof motion compared to a trolley with a lower velocity and it is more

difficult to stop a heavy trolley which is moving at the same velocityas an empty trolley. SPM P2E07 2. The resistance of an object to a change in its state of motion is

known as momentum. 3. The total momentum before and after the collision is the same. P1’06

P2’S12 4. The linear momentum, p of an object of mass, m, which is moving

with a velocity, v, is defined as the product of mass andvelocity. SPM P2E07 p = m x v

5. The unit of momentum is kg ms-1.

6. Momentum is a vector quantity and acts in the same direction asthe velocity. When the positive sign is used to represent the right

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direction, then the left direction is represented by the negative signand vice versa.

7. When the velocity increase, momentum increases. SPM P2E07

Conservation of Momentum1. The principle of conservation of momentum states that:

that: P2’S12

The total momentum of a system is constant,if no external force acts on the system.

2. Examples of external force are friction, air resistance, etc.3. A balloon is tied to arod when the air is released, a backward

momentum is produced.4. The principle of conservation of momentum is applied in twosituations:

a. Collision (elastic and inelastic)b. Explosion

Collisions

EXPERIMENT SPM 05 P3 KDH’14, PP’14, PHG’14

Aim : To verify the principle of conservation of momentum in elastic and

inelastic collisions

Problem : Is momentum conserved in elastic and inelastic collisions?

Hypothesis : Momentum is conserved in elastic and inelastic collisions.

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Apparatus/Materials

(A) Elastic collisionArrangement of Apparatus

Procedure

1. The apparatus is arranged as shown in Figure 2.13.2. The track is adjusted until it is friction-compensated.3. Trolley A with a spring-loaded piston is placed at the higher end of

the runway while trolley B is placed at the middle of the runway.Ticker tapes are attached to both trolleys.

4. When the ticker-timer is switched on, trolley A is pushed slightly sothat it moves down the track with a uniform velocity and collides withtrolley B.

5. After the collision, the trolleys move separately and the ticker tapesare used to calculate the velocities of trolleys A and B before andafter the collision.

6. Assuming that the mass of each trolley is 1 unit, the momentumsbefore and after the collision are calculated.

7. The experiment is repeated using:a. 1 trolley to collide with 2 stationary stacked trolleysb. 2 stacked trolleys to collide with 1 stationary trolley

Results

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Discussion

1. The spring-loaded piston is used to separate the trolleys aftercollision.

2. In practice, the collision is not a perfectly elastic collision as part of

the kinetic energy is converted into sound or heat when the trolleyscollide.3. Table 2.4 shows that the total momentum before collision equals the

total momentum after collision.

ConclusionThe momentum is conserved in an elastic collision. The hypothesis isaccepted.(B) Inelastic collisionArrangement of Apparatus

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1. Some plasticine is attached to both trolleys as shown in Figure 2.15.2. A ticker tape is attached to trolley A only.3. When the ticker-timer is switched on, trolley A is pushed slightly so

that it moves down the track with a uniform velocity and collides withtrolley B.

4. After the collision, the trolleys move together and the ticker tape isused to calculate the initial velocity of trolley A before the collisionand the common velocity of combined trolleys A and B after thecollision.

5. Assuming that the mass of each trolley is 1 unit, the momentumsbefore and after the collision are calculated.

6. The experiment is repeated using:a. 1 trolley to collide with 2 stationary stacked trolleys

b. 2 stacked trolleys to collide with 1 stationary trolley

Results

1.

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2. Tabulation of data

Discussion

1. The plasticines are used to attach the trolleys after collision.2. Table 2.5 shows that the total momentum before collision equals the

total momentum after collision.

ConclusionMomentum is conserved in an inelastic collision. The hypothesis isaccepted.

ExplosionsExample 1 SPM 08

1. A balloon filled with air, moves upwards with a certain momentumwhen air is released from the bottom of the balloon. The air whichhas mass and moves with a velocity, produces a backwardmomentum which then causes the balloon to move upwards with thesame momentum.

2. The total momentum before the explosion is zero as the velocities ofthe balloon and air are zero.

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3. The total momentum after the explosion is still zero as the upwardmomentum is equal to the downward momentum.

4. Therefore, the principle of conservation of momentum is obeyed.

Examp le 2

1. Before explosion, both the bullet and the rifle are at rest. The totalmomentum is zero.

2. When the rifle is fired, the bullet which has mass and moves with avelocity, produces a forward momentum. This causes the rifle torecoil backwards with a backward momentum which has the samemomentum as the bullet.

Therefore, the total momentum after the explosion is still zero and itcan be written as:

m1 v1 + m2 v2 = 0

Rearranging the formula gives:

m1 v1 = – m2 v2

where the negative sign indicates the opposite direction. Since themagnitudes are equal, the equation can be written as:

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m1 v1 = – m2 v2

Other applications of explosions are rocket propulsion and jet

propulsion for airplanes.Examp le 3

1. A running athlete2. Momentum of the hand moving backwards = momentum of the body

moving forward SPM 10

EXPERIMENT **acceleration and force PHG’14, MLK’14

Aim : To investigate the relationship between the acceleration and mass of an

object under a constant forceProblem : Two identical trolleys, one empty and the other filled with heavy loads,

are pushed with a constant force. The empty trolley moves with a higher

velocity in a shorter time (acceleration). What is the relationship between

acceleration and mass?

Inference : The mass of an object affects its acceleration.

Hypothesis: The acceleration of an object decreases when its mass increases.

Variables

1. Manipulated: Mass of trolley, m 2. Responding: Acceleration of trolley, a 3. Fixed: Force applied, F

Apparatus / Materials

3 identical trolleys, elastic string, friction-compensated track, ticker-timer, ticker tape, 12V a.c. power supply and a wooden block.Arrangement of Apparatus

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Procedure

1. The ticker-timer is switched on and the trolley is pulled down thetrack with the elastic string attached to the trolley.

2. The elastic string is stretched until it reaches the front of the trolley

and the length is maintained as the trolley moves down the track.3. The ticker tape from the experiment is cut into strips of 10 ticks. A

tape chart is constructed and the acceleration is determined.4. Steps 1, 2 and 3 are repeated using 2 and 3 trolleys (trolleys are

stacked up on each other) to increase the mass of the trolley. Theelastic string is stretched to the same length as in the experimentusing 1 trolley.

Results

1. Tape chart:

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2. Tabulation of data:

Data AnalysisGraph of acceleration, a, against mass, m, and graph ofacceleration, a, against inverse of mass, 1

⁄ m

Discussion

1. When the number of trolleys used is increased, the mass of thetrolley increases. As a result, the acceleration of the trolley decreases.

2. The gradient of the tape chart decreases as the number of trolleysincreases which indicates the decrease in the acceleration of thetrolley.

ConclusionThe acceleration of an object is inversely proportional to its masswhen, the force acting on it is constant. The hypothesis is accepted.PrecautionThe position of eye perpendicular to the scale of the metre rule toavoid parallel error

Force

PHG’14

1. A force (vector quantity) is a push or a pull on an object, unit newton(N).

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2. Effect of a force:a. Moves a stationary objectb. Changes the velocity of a moving object in magnitude or in direction

or both

c. Can decelerate or stop a moving objectd. Changes the size of shape of an object.3. Newton’ second law of motion states that the rate of change of

momentum is directly proportional to the resultant force and in thesame direction as the force.

4. To produce motion, the forward force > backward force +friction SPM 05

5. Mass does not effect the force that applied that applied.

Impulse and Impulsive Force

1. The impulse (vector quantity) of a constant force F is defined as theproduct of the force and the time t for it acts.

Impulse = Ft

2. A golfer continue his swing after hitting the ball: P2’E12 o to increase impulse on the ballo the time of contact increaseo change of momentum increaseso the speed increases3. Impulse force is defined as the rate of change of momentum. SPM

07 P2’ E12 PP’14 PP’14

PP’14

4. Front and rear sections of car designed to crumple easily,to increase impact time. As time of impact increases, a smallerimpulsive force results. SPM 07

5. Ways to reduce impulse force;1. Thick mattress will lengthen the time impact on landing, thus

reducing the resultant impulsive force. SPM 05 2. Basket ball player moves his hand backwards when catching the ball.

Thus, prolong the time of impact and reduce the impulsive forceacting on his palm.SPM 09

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3. The parachutist bends his kegs to lengthen the time ofimpact/collision. This reduces the impulsive force acting on hislegs. SPM 06//11

6. The earth is surrounded by a gravitational field which exerts a force

on any body in the field is called the force of gravity, unit Nkg

-1

.7. The force of gravity acting on an object is called weight (vectorquantity), unit newton (N). SPM P2S05

-> g = acceleration due to gravity

8. Design a helmet: . Fibre glass shell also crush on impact thus absorbing impulsive force give better protectiona. Polysrtyrene as inside good absorber shock give protection for head provide comfortb. Full-face helmet provide a large area of protection of headc. not too heavy

9. Characteristics of the rope to make the parachute: PHG’14

*

Forces that act on the parachute during decending: Lifting force, gravity, thrust

force, dragging force

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Forces in Equilibrium EXAM TIPS

1. When forces are in equilibrium or when forces are balanced, the net

force or resultant force, FR is zero. The object at this moment willeither be stationary / at rest or moving with uniformvelocity (zero acceleration). SPM 07/08/09 & P2S05 MLK’14

2. Normal reaction, R and the weight, W (mg) are acting in oppositedirections. SPM 11 MLK’14 So the resultant force is the subtractionof the two forces. SPM P2S05

3. An example of forces in equilibrium:a. A television placed on a table.

When the forces are in equilibrium:Normal reaction force, R= Weight of television, W (= m£)

* The television is stationary.

b. A skydiver falling at terminal velocity. When the forces are inequilibrium: Air resistance, G= Weight of object, W (= mg)

* The object falls with a uniform velocity.

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SPM 07.

c. A car descending a hill at constant velocityd. A lamp is hanging at rest in halle. A ship floating at rest in the sea

1. When two forces are parallel to each other, the addition can be doneby simple arithmetic.>

a. Forces acting in the same direction

b. Forces acting in opposite directions SPM 07/08

2. Frictional Force is force which opposes movement.

3. When two forces are neither parallel nor perpendicular to ea other,there are two methods to calculate the resultant force.

a. Triangle method P1’07/12 When the forces do not start from the same point, a force diagramcan be drawn to obtain the resultant force, FR. A force diagram is arepresentation of forces with their respective magnitudes anddirections.

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i. The diagram is drawn to a suitable scale.ii. F1 is drawn first, followed by F2.iii. The resultant force is then drawn from the beginning of F1 to the end

of F2 iv. The value of the resultant force is measured from the length of AC

and the direction of the resultant force is < CAB.b. Parallelogram method

When the forces start from the same point, a vector diagram is drawn

to obtain the resultant force, FR.

i. A suitable scale is used in this drawing and both F1 and F2 are

drawn from the same point.ii. Complete the drawing using a pair of compasses and then draw thediagonal of the parallelogram.

iii. The diagonal represents the magnitude and direction of the resultantforce, FR.

4. When two forces are perpendicular to each other, Pythagoras'theorem and the parallelogram method can be applied to obtain theresultant force.

Resolution of Forces

1. The resultant force is found by combining the forces. The reverseprocess where a single force is split into two components is known as

the resolution of forces.

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2. The two components of force are the vertical force, Fy and thehorizontal force, Fx. They are perpendicular to each other in aparallelogram. PHG’14

3. Simple trigonometry is applied to obtain the values of Fx and

Fy . PHG’14, MLK’14

Inclined Plane MLK’14

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A boy in a lift SPM P2S05 PP’14

1. When the lift moves up with acceleration, the normal reaction isgreater than his weight. R > W, W = mg, R – W = ma SPM 06

2. There is a resultant force acting upwards, f=ma SPM 07/10 &P2E07 PHG’14 due to its acceleration.

3. Normal reaction is equal to the sum of the boy’s weight and theresultant force, R=mg+ma.

4. When the lift moves down, weight reduces.5. Because W > R or R = W – ma .

Modifications to avoid string from being broken MLK’14

a. Type of material of spring: Nylon (reason: strong material)b. Angle of pulling force, F from vertical line, Ø:Use smaller angle

(reason: reduce magnitude of tension of the spring)

Work done, Energy, Power and Efficiency EXAM TIPS

1. Work done (scalar quantity) defined as the force applied multipliedby the displacement of an object in the direction of the force, unit

joule (J). SPM P2S05 & 07

SPM 06/07 & P206

2. Some work is used to overcome frictional force. SPM P207 3. A person pushes a wall. There is no displacement, thus no work is

done. SPM 08 4. Energy (scalar quantity) is defined as the ability of a system to do

work, unit joule (J).5. Energy due to motion called kinetic energy.

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Example: Kinetic energy increases when a book is falling.

6. The principle of conservation of energy SPM P2S06 states thatenergy can be transferred from one form to another, but it cannot becreated or destroyed. SPM 11

7. Power is defined as a measure of the rate of work done P2’E12 orenergy changed or transferred. SPM 11 PHG’14

8. The efficiency of a device is defined as the percentage of the energyinput that is transformed into useful energy.

9. Racing car is design use light composite material for making the bodyof car, acceleration increases when mass decreases.

10. A trainer with consistent time over a longer period can bechoose to compete in 1500m race.

Gravity

1. Gravitational fall, F=mgSince g is a constant, when an object falls, F is directly proportionalto m. SPM 09

2. Weight is gravitational force (the pull of gravity) PHG’14 3. The acceleration of all failing objects is influenced by the earth

gravitational force. SPM 09 4. When weight is released, energy change: SPM 10

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The potential energy of the weight -> kinetic energy of the woodenblock & weight

5. Gravitational potential energy of an object is the energy possessedby the object due to its higher position in the gravitational field.

SPM 06/11 & P207 -> g = acceleration due to gravity (ms

-2).

Example 1: As the student running up the stairs, h increases, soE p also increases. Thus, E p α h. SPM 05 Example 2: when objects (big or small mass) are in free fall PP’14,

they experience the same acceleration SPM 06,i.e. gravitational acceleration. SPM 06 thefalling time are thesame. SPM 10 & P2S06

Elasticity

1. A property of matter that enables an object to return to its originalshape and size after the force acting on it is removed. KDH’14,

PHG’14, 2. Hooke's law states that:

The change in length of a spring is directly proportional to the forceapplied to the spring without exceeding the elastic limit of thespring. SPM 06 graph

3. Figure 2.59 shows a graph of applied force against extension of aspring (F-x graph). The straight line passing through the origin showsthat the applied force is directly proportional to the extension of the

spring. Hooke's law is obeyed.

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4. After the elastic limit, the graph curves where the applied force doesnot vary directly to the extension of the spring and Hooke's law is no

longer obeyed. When the load is removed, the spring is not able toreturn to its original state.

5. Based on the straight line in the F- x graph in Figure 2.59,

where k is a constant known as spring constant and the unit of k is

N m. SPM 05

6. From Hooke's law: F = kx

Applying y = mx + c,

7.

8. Hence, the gradient of the F-x graph represents the springconstant, k .

9. The area under the straight line of the F-x graph represents theelastic potential energy, E p.

Area under the graph, A = E p =1 ⁄ 2 Fx

Substituting F = kx , E p =1 ⁄ 2 ( kx )( x )

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10. The spring constant, k is a measure of the elasticity or thestiffness of the spring.

11. The bigger the spring constant, the higher the stiffness of thespring. KDH’14

12. To investigate about stretching of a spring by support differentof mass: SPM 09 a. Manipulated: Mass of an objectb. Responding: Length of spring/ Extensionc. Constant: Diameter of spring13. Based on the graph of displacement-time: SPM 07 a. O is the point of the equilibrium.b. At O, the spring has maximum kinetic energyc. At P or Q, the spring has maximum elastic potential energy.d. At p or Q, the displacement of the load is maximum.

14. Oscillation is a motion of a body back and forth along a lineabout a fixed central point.

15. Velocity does not depend on mass. Velocity depends on height.Potential energy = kinetic energy

16. The oscillation is clamped due to the resistant affair.

Factors that Affecting the Elasticity / Stiffness of a Spring[Hooke’s Law]

KDH’14, PHG’14

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SPM 07 P3 SPM 13 P2

PHG’14

Aim : To investigate the relation between the period of oscillation

of a loaded spring and the mass of its load.Manipulated variable : Mass of the load

Responding variable : Period of oscillation

Constant variable : The type of spring/spring constant

List of apparatus and

materials

: Retort stand and clamp, spring, slotted weights, stopwatch.

Arrangement of apparatus

Procedure

i. Measure the time of 10 oscillations using a stopwatch and the initialload of 50 g.

ii. Calculate the period of one oscillation.iii. Repeat the experiment four limes using loads of 100 g, 150 g, 200 g,

and 250 g.

Tabulation of data

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Analysis of data

Drawing a conclusion :The period of oscillation. (J) increases when the mass of the load (m)increases

Experiment: To investigate the relationship between the extension of a spring and the

stretching force MLK’14

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