TEKNIK MENJAWAB FIZIK

SPMKERTAS 2

Physics Paper 2 (2 ½ hours)

Section A (60 marks)

Section B(20 marks)

Section C (20 marks)

1 ½ h ½ h ½ h

8 structure 2 essay (answer 1 only)

2 essay (answer 1 only)

2 essays *Compare 2 diagram

*Open Response

*Characteristics in table*Close

Response

SECTION A

• Time management (60 x 1.5 = 90 minutes)• All calculation must show:

1) formula

2) substitute value

3) final answer with unit• Observe & Explain (observe = spot the difference)

• Definition (can use formula but state…)• Answer in short sentence• Relate/Relationship (…..bigger, ….. bigger)

TIPS (Section A)

Section A1. Diagram 5.1 shows two boys pushing a large box. After some

time, the box still remains stationary. Diagram 5.2 shows an aircraft moving forward with a uniform velocity at a constant height.

(a) Based on the situation in D 5.1 and the situation in D 5.2, (i) state similarities about the magnitudes and directions of the forces F1 and F2, F3 and F4. [2 marks]

Magnitudes: F1 = F2 ; F3 = F4 // SAMEDirections : OPPOSITE

SPM 2008

(ii) What is the net force in both situation?[1 mark]

Zero // 0 N// 0(iii) Based on the answers in 5(a)(i) and 5(a)(ii),

name the physics concept involved. [1 mark]

Forces In Equilibrium // Newton 3rd Law(b) (i) Another aircraft has F3 greater than F4.

Describe the motion of this aircraft. [1 mark]

accelerate

(ii) Explain the answer in 5(b)(i). [2 marks]

Net Force is not zero

F = ma where m= mass, a =acceleration

2. Diagram 6.1 and Diagram 6.2 show two circuits with identical components. Each circuit contains an ammeter, a cell and a semiconductor diode.

(a) Give one example of a semiconductor material.[1 m]

Boron // Indium // Galium

SPM 2008

(b) Observe Diagram 6.1 and Diagram 6.2. State the difference between:(i) The connection of the diodes. [1 mark] Anode of the diod is connected to positive

terminal of the cell in Diagram 6.2(ii) The reading of the ammeters. [1 mark]

Diagram 6.1 is 0A, Diagram 6.2 is > 2A

(c) Give two reasons that cause the difference between the reading of the ammeters in Diagram 6.1 and in Diagram 6.2. [2 marks]

Diagram 6.1 :

Diode is reverse biased & bigger depletion layer

or

Diagram 6.2 :

Diode is forward biased & smaller depletion layer

(e) Diagram 6.3 shows the output signal displayed on the screen of a cathode ray oscilloscope (CR0) when a diode is connected to an a.c. power supply.Explain why the output signal is produced as shown. [2 marks]

Diode acts as half wave rectifier

Diode is forward biased when current is at positive cycle

1. Diagrams 5.1 and 5.2 show instrument K being used to measure pressure for a fixed mass of gas in an air-tight container.

(a) Name the instrument K. [1 mark]

Bourdon Gauge

MRSM 2008

(b) Based on the observations of Diagrams 5.1 and 5.2, (i) compare the volume of the gas. [1 mark]

Diagram 5.1 is greater(ii) compare the pressure of the gas [1 mark]

Diagram 5.1 is smaller(iii) state one assumption made while performing the

experiment. [1 mark]The Temperature of the gas is constant

(c) Using your answers in (b)(i) and (b)(ii), sketch the graph of pressure against volume of the gas. [1 mark]

(d) Name the physics law which is involved in the above observation. [1 mark]

Boyle’s Law

Volume

Pressure

SECTION B

Section B(a) Diagram 9.1 shows two identical steel balls placed

onto spring M and spring N. Both springs are elastic and fixed to a horizontal surface. The springs are pushed down until the lengths of spring M and spring N are the same.

• Diagram 9.2 shows the maximum heights reached by the balls when the hands are released.

• [Assume spring M and spring N are of the same material, same coil diameter and same original length

(i) What is the meaning of elasticity? [1mark]

• The property of an object to enable it to return to its original shape and dimension/size when the applied force is removed

(ii) Using Diagram 9.1 and Diagram 9.2, compare the thickness of the spring wire and the maximum height reached by the balls. Relate the thickness of the spring wire with the maximum height of the ball to make a deduction regarding the relationship between the thickness of the spring wire and the elastic potential energy of the spring. [5 marks]

/1: Spring wire in 9.1(a) is thinner//9.1(b) is thicker or Spring wire M is thinner// N is thicker

/2: Maximum height reached by the ball in 9.2(b) is higher//9.2(a) is lower or Maximum height reached by the ball on spring N is higher//M is lower

/3: The thicker the spring wire, the higher the maximum height reached by the ball

/4: the higher the maximum height reached by the ball, the higher the elastic potential energy of the spring

/5:The thicker the spring wire, the higher the elastic potential energy of the spring

• (b) The forces used to compress the springs in Diagram 9.1(a) and Diagram 9.1(b) are F1 and F2 respectively.

• (i) Compare F1 and F2. • Give one reason for this answer. [2 marks]

/1: F2 > F1/2: Spring N is stiffer

• (ii) Using Diagram 9.1 and Diagram 9.2, state the energy changes that take place from the moment the spring is compressed until the ball reaches its maximum height. [2 marks]

/1 : Elastic Potential Energy --> Kinetic Energy

/2 : Kinetic Energy ---> Gravitational Potential Energy

• Diagram 9.3 shows a pole vaulter performing a jump.

• Using appropriate physics concepts, explain the use of suitable equipment and techniques to improve his performance.

• Your answer should include the following aspects:

(i) Vaulter’s attire

(ii) Vaulter’s movement

(iii) Pole used

(iv) Safety

Movement

Attire / Shirt

ShoesPole

Mattress

Pole Vaulter Motion

Tight Attire / Shirt : Reduce air resistance

Strong/ Less Dense/ Elastic Pole

Spike Shoes

Movement: Moves faster//increase speed,

bigger momentum// bigger kinetic energy

Thicker/Softer Mattress

Aspects Characteristic Explaination

Attire

Tight/BodyShape Reduce air resistanceSpike Shoes Reduce surface area, increase

pressure, increase grip, increase friction

Movement

Moves faster// increase speed,

bigger momentum// bigger kinetic energy

Pole

Elastic Pole Can be bend easily,> elastic PE, > gravitational PE

Made from less dense material

Reduce the mass. Hence, lighter

Safety

Thicker // Softer mattress

Increase time of impact, reduce impulsive force, less injuries

SECTION C

SPM 2007

Diagram 11.1 shows the speed limit and the load

limit of heavy vehicles such as buses and lorries.

(a) What is meant by speed? [1 m]

Speed is rate of change of distance

Using the concepts of momentum and inertia, explain why the speed limit and the load limit must be imposed on heavy vehicles. [4 m]

• Momentum = mass x velocity• Smaller velocity (speed), smaller momentum• Inertia = the tendency of an object to resist

its state of motion• Smaller mass, smaller inertia

(b)

momentum inertia

speed load = mass

(c) Diagram 11.2 shows four tankers, P, Q, R and S, with different specifications. You are required to determine the most suitable tanker to deliver oil safely. Study the specifications of all the four tankers from the following aspects:

• The type of brakes • The number of tyres • The number and size of the tanks • The distance between the trailer and the tractor • Explain the suitability of the aspects.• Justify your choice. [10 marks]

Characteristic Explaination

Type of brakes is Antilock brake system

prevent wheels from locking // prevent skidding// more efficient

The tanker must have many tyres

to increase surface area hence reduce pressure // lower the centre of gravity hence increase stability

The tanker should have more and Smaller size of the tanks

to reduce the negative effect of inertia

The distance between the trailer and the tractor should be further

easy to make turn // avoid trailer from crushing the tractor when emergency stop

Choice : R

• Type of brakes = ABS

(Antilock Brake System)• 2 // more tyres• 5 small tanks • have distance between the trailer

and the tractor

(d) A tanker of mass 1 800 kg accelerates from rest to a velocity of 45 km/h in 10 s. [5 marks]

(i) Calculate the acceleration of the tanker.

a = (v - u)/t

a = [45 x 103/ 3600 ] / 10

= 1.25 m s-2

(ii) Calculate the force acting on the tanker.

F = ma

= (1800)(1.25)

= 2250 N

Thank You