SULIT 1 4531/2

SMK SERI BINTANG SELATAN, SEKOLAH KLUSTER KECEMERLANGAN

KUALA LUMPUR

PEPERUKSAAN PERTENGAHAN TAHUN 2014TINGKATAN EMPAT

FIZIKKERTAS 2

PERATURAN PEMARKAHAN

4531/2FizikKertas 2MEI20142 ½ Jam

SULIT 2 4531/2

Question Number

Mark scheme Mark

1 a. PQRQP 1 b.(i) (ii)

0.245.0

11

c. Scalar quantity 1total 4

2 (a) Ratchet 1 (b) To ensure the pressure exerted does not exceed // undue pressure is not

exerted1

(c) -0.02mm 1 (d) 0.01 mm 1

Has smaller scale division 1Total 5

3 (a) 0.02 s 1 (b) Increasing velocity// constant acceleration 1 (c) (i) 1

(c) (ii) 1

(d)

1

1Total 6

4 (a) Rate change of displacement 1 (b) 1

(c) (i) 1

1(c) (ii)

OR

2

1

R

SULIT 3 4531/2

Total 75 (a) change of momentum 1 (b) OP > OQ 1 (c) (i) Impulsive force 1 (ii) 5.1(a) < 5.1(b) 1 (iii) The shorter the time, the larger the impulsive force/ vice versa 1 (iv) Inflate the ball/ pump air into the ball 1 (d) To increase the time impact

So it will decrease the impulsive force11

Total 86 (a)

2

(b) 200 N 1 (c) (i) Diagram 6.1 : Fy = F sin θ = 50 sin 300 = 25N 1 Diagram 6.2 : Fy = F sin θ = 50 sin 300 = 25N 1 (ii) Diagram 6.1 : F act on ground = W – Fy = 200 N + 25 N = 250 N 1

Diagram 6.2 : F act on ground = W + Fy = 200 N - 25 N = 180 N 1 (d) Force exert on the ground in Diagram 6.1 is more than Diagram 6.2 1

Total 87 (a) Rate change of displacement 1 (b) 7.1 < 7.2 1 (c) (i) P > Q 1 (ii) acceleration 1 (iii) cms-2 1 (d) The higher the mass, the lower the acceleration 1 (e) Suggestion : Increase the height of the runaway 1

Reason : The change of velocity will increases 1Suggestion : Use friction compensated runaway / smooth surface 1Reason : The net force produced will be increases 1* tambah elastic cord tak boleh sebab kita nak force constant.* kurangkan mass pun tak boleh sebab itu memang dah manipulated

variableTotal 10

8 (a) object falls with an acceleration due to gravity only 1 (b) Gravitational force

Impulsive force11

(c)

(mcm tak logic tapi kira betul la kan)11

SULIT 4 4531/2 (d) W= mg

= 2.5 kg x 10ms2

= 25 N // 25 kgms-2 1 (e) Mass is base quantity, weight is derived quantity// mass does not affect

by gravity, weight does affect by gravity1

(f) Gravitational potential energy// potential energy to kinetic energy 1 (g) Material Q

Soft surfaceWill increase the time impactReduce the impulsive force

1111

Total 12

SECTION B9. (a) Momentum is product of mass and velocity 1 (b) 10.1 shape does not change, 10.2 ball flattened//change shape

10.1 higher velocity than 10.2Time of impact of 10.1 shorter than 10.2The higher the time impact, the lower the impulsive forceThe higher the velocity, the higher the impulsive force

11111

(c) A soft ball has a high velocity. A soft ball has a high momentum. The soft ball player move his hand backward to increase time impact. The higher the time impact will reduce impulsive force.

1111

(d)Modification ExplanationFront and rear crumple zones

-to increase time of impact to reduce impulsive force.

Air bags

-to prevent driver and passenger colliding with steering wheel and dashboard.-to increase time of impact to reduce impulsive force.

Dashboard – made of soft material

to lengthen the time of impact so as to reduce impulsive force.

Seat belt to prevent passengers thrown foward due to it inertia

Headrest to prevent head thrown back due to it inertiaANY POSSIBLE ANSWER.

2

2

2

2

2

Total 20SECTION C

10 (a) The property/tendency of the material to return to their original shape and size when the force exerted on it is removed.

1

(b) - There are two types of force- Attraction and repulsive force between the particles of the solid.- When the solid is stretched, the molecules displaced away from each other- Attractive forces are acting to oppose the stretching- When the solid is compressed, the molecules displaced closer to each other- Repulsive forces are acting to oppose the compression

11

1

1

1

SULIT 5 4531/2

(c) Specification ExplanationSmall diameter of coil Enough space for the spring to be install

More than 1000 N /higher elastic limit Can support motorcyclist up to 100 kg

Higher spring constant Small compression on a spring

Made up by steel Strong and cannot break easily / stronger than iron

Choosen DBecause the spring is small diameter coil, elastic limit is more than 1000 N, higher spring constant and made by steel.

2

2

2

2

2

(d) (i) Spring Q

because it have larger slope than Q / larger spring constant.(ii) E = 1 F x 2

So EQ = 1 (4)(0.08) = 0.16 J 2 EP = 1 (2)(0.08) = 0.08 J 2 Kalau tidak guna pada J guna N cm-1 . Boleh kan kak han? Jika jawapan pelajar Eq =16 N cm-1 Ep = 8 N cm-1

11

11

Total 20

PERATURAN PEMARKAHAN TAMAT

Disediakan oleh, Disemak oleh,

……………………… ……………………………..(NORMALA BINTI OMAR) (NORREHAN BINTI AHMAD NAWAWI) Guru Fizik Ketua Panitia Sains B

Disahkan oleh,

…………………………(PN KAMARIAH @ CHE SEAH BINTI CHE ABDUL RAHMAN)Pengetua