ANSWER

SKEMA UJIAN 2 FIZIK

TINGKATAN 4BAHAGIAN A

1A6B11B16C

2B7C12B17D

3A8D13C18C

4A9A14C19C

5B10A15A20E

BAHAGIAN B

1) (a)(i) pressure/tekanan = 20 /(5 x 10-4) = 40 kPa.

(ii) weight of load/berat baban, W = 20 x (50/5) = 200 N.

(iii) distance moved/jarak yang dilalui = (5 x 4)/50 = 0.4 cm

(b) Pascals principle/Prinsip Pascal(c) The pistons are frictionless.

Tiada geseran pada omboh.2) (a)(i) mass per unit volume of a certain material.

jisim per unit isipadu(ii) 7.5 x 1000 = 7500 kg m-3.

(b) (i) 5 x 10 x 20 = 1000 cm3 = 1000 x 10-6 m3 = 10-3 m3(ii) weight = mass x acceleration due to gravity

= volume x density x acceleration due to gravity

berat = jisim x pecutan graviti

= Isipadu x ketumpatan x pecutan graviti = 10-3 x 7500 x 10

= 75 N

(c )(i)

(ii) Maximum pressure = weight of wooden block / area

tekanan maksimum = berat bungkah kayu / luas = 75/(5 x 10-2 x 10 x 10-2)

= 1.5 x 104 N m-2.3) (a) When an object is partially or fully immersed in a fluid, the object experiences a buoyant force that is equals to the weight of the fluid displaced.

Bila sebuah objek direndamkan separa atau sepenuhnya dalam cecair, objek itu akan mengalami julangan yang sama dengan berat cecair yang disesarkan.(b)(i)

(ii) 20 cm3(iii) weight of block of wood

berat bungkah kayu

= (48 x 10-6)(800)(10) = 0.384 N

(iv) buoyant force/julangan = weight of wood = 0.384 N BAHAGIAN C1) a) Pascals principle states that the pressure applied to an enclosed fluid is transmitted evenly throughout the fluid.

Prinsip Pascal menyatakan bahawa tekanan yang dikenakan dalam cecair yang terperangkap dipindahkan dengan seragamnya ke seluruh cecair.b) When the brake pedal is pressed, pressure exerted in the master cylinder is transmitted via the hydraulic fluid to the wheel cylinder thus forcing the brake shoe to function to slow down the car. When the pressure on the foot pedal is released, the spring forces the piston back into the wheel cylinder, thereby terminating the contact between the brake shoe and the wheel.Bila pedal brek ditekan, tekanan dikenakan dalam silinder utama dan dipindahkan menerusi cecair hidraulik ke silinder roda menyebabkan kasut brek berfungsi memperlahankan kereta. Apabila tekanan pada pedal kaki dilepaskan, spring menarik omboh balik ke dalam silinder roda, menyebabkan sentuhan antara kasut brek dan roda dimatikan.(c) (i) rate of wear and tear low so that the brake shoe can last longer. Melting point high so that the brake shoe doesnt soften when in use. Coefficient of friction high so that the braking is effective. Specific heat capacity high so that the temperature of the brake show will not increase dramatically.

haus dan lusus - boleh tahan haus dan lusuh - supaya brek dapat tahan lebih lama. Takat lebur - tinggi - supaya kasut brek tidak akan jadi lembut bila digunakan. Koefisien geseran - tinggi - supaya kesan membrek adalan tinggi. Muatan haba tentu - rendah - tinggi - supaya suhu tidak ajan naik dengan cepat.(ii) Material Q because its rate of wear and tear is low, its melting point is high, its coefficient of friction is high and it have a high specific heat capacity.

Bahan Q kerana kadar haus dan lusuh adalah rendah, takat leburnya tinggi, koefifien geserannya tinggi dan muatan haba tentunya tinggi.