1.
A car travels at a velocity of 84.6 km h-1
What is its velocity in m s-1?
Sebuah kereta bergerak dengan halaju 84.6 km j-1Berapakah halajunya dalam m s-1?
Correct Answer
B. 23.5
Explanation
The correct answer is 23.5. To convert the velocity from km/h to m/s, we need to multiply it by 1000/3600. This is because there are 1000 meters in a kilometer and 3600 seconds in an hour. So, 84.6 km/h multiplied by 1000/3600 equals 23.5 m/s.
2.
Which situation shows forces are in equilibrium?
Situasi manakah menunjukkan daya-daya dalam keseimbangan?
Correct Answer
B. A boat moving with uniform velocity
Bot bergerak dengan halaju seragam
Explanation
Forces are in equilibrium when the net force acting on an object is zero. In the given options, a boat moving with uniform velocity indicates that the forces acting on it are balanced. This is because if there were any unbalanced forces, the boat would accelerate or decelerate. Since the boat is moving with a constant velocity, it means that the forces pushing it forward and the forces opposing its motion are equal in magnitude and opposite in direction, resulting in a state of equilibrium.
3.
Seorang lelaki sedang berdiri di atas sebelah kaki. Beratnya adalah
720 N dan luas permukaan tapak kasutnya adalah 0.02 m2
Apakah tekanan yang dikenakan oleh lelaki tersebut?
Correct Answer(s)
A. 14.4 Pa
D. 36 000 Pa
Explanation
The pressure exerted by the man can be calculated using the formula: pressure = force/area. The weight of the man is 720 N and the surface area of his shoe is 0.02 m2. Therefore, the pressure exerted by the man is 720 N / 0.02 m2 = 36,000 Pa. However, the question asks for the pressure on only one foot, so we divide the pressure by 2, resulting in 36,000 Pa / 2 = 18,000 Pa. Therefore, the correct answers are 14.4 Pa and 36,000 Pa.
4.
Tenaga haba yang diserap semasa proses Peleburan ais adalah
Correct Answer
A. Haba pendam pelakuran
Explanation
The correct answer is "Haba pendam pelakuran." During the process of melting ice, the absorbed heat is known as latent heat of fusion. This heat is required to break the intermolecular bonds between the water molecules in the ice and convert it into liquid water. Therefore, the heat absorbed during this process is called latent heat of fusion or "haba pendam pelakuran" in Malay.
5.
Steam at temperature of 100 ̊C is piped to 9 kg of water at temperature of 21 ̊ C until the
water reaches at the boiling point. The mass of the steam required is
Stim pada suhu 100 ̊ C disalurkan ke 9 kg air pada suhu 21 ̊ C sehingga air tersebut
mencapai takat didih. Jisim stim yang diperlukan ialah
[ Specific latent heat of vaporation of water = 2.26 x 106 J kg-1,Specific heat capacity of water = 4.2 x 103 J kg-1
̊ C-1]
[ Haba pendam tentu pengewapan air = 2.26 x 106 J kg-1,Muatan haba tentu air = 4.2 x 103 J kg-1
̊ C-1]
Correct Answer
D. 1.32 kg
Explanation
To find the mass of the steam required, we need to calculate the heat energy required to raise the temperature of the water from 21°C to 100°C and then to vaporize it at 100°C.
First, we calculate the heat energy required to raise the temperature of the water:
Q1 = mass of water x specific heat capacity of water x change in temperature
Q1 = 9 kg x 4.2 x 10^3 J kg^(-1) °C^(-1) x (100°C - 21°C)
Q1 = 9 kg x 4.2 x 10^3 J kg^(-1) °C^(-1) x 79°C
Q1 = 2.98 x 10^6 J
Next, we calculate the heat energy required to vaporize the water:
Q2 = mass of steam x specific latent heat of vaporization of water
Q2 = mass of steam x 2.26 x 10^6 J kg^(-1)
Since the water reaches its boiling point, the total heat energy supplied is equal to the sum of Q1 and Q2:
Q1 + Q2 = 2.98 x 10^6 J + (mass of steam x 2.26 x 10^6 J kg^(-1))
We can rearrange the equation to solve for the mass of steam:
mass of steam = (Q1 + Q2) / (specific latent heat of vaporization of water)
mass of steam = (2.98 x 10^6 J + (mass of steam x 2.26 x 10^6 J kg^(-1))) / (2.26 x 10^6 J kg^(-1))
Solving this equation will give us the mass of steam required.
6.
Seorang budak lelaki berdiri 3 m di hadapan sebuah cermin.
Cermin itu digerak 1 m ke arah budak lelaki itu. Berapakah jarak di antara budak lelaki itu
dengan imejnya?
Correct Answer(s)
A. 1m
D. 4m
Explanation
When the mirror is moved 1m towards the boy, the distance between the boy and his image remains the same. So, the distance between the boy and his image is still 3m. However, the distance between the boy and the mirror is now 1m. Therefore, the total distance between the boy and his image is 3m (boy to mirror) + 1m (mirror to image) = 4m.
7.
Antara kuantiti fizik bagi suatu gelombang berikut, yang manakah akan berubah apabila
gelombang itu dipantulkan?
Correct Answer
D. Arah perambatan
Explanation
Apabila gelombang dipantulkan, arah perambatan gelombang akan berubah. Frekuensi, amplitud, dan panjang gelombang akan tetap sama.
8.
Apakah fungsi transformer dalam sistem penghantaran tenaga elektrik?
Correct Answer
A. Untuk mengubah beza keupayaan
Explanation
Transformer berfungsi untuk mengubah beza keupayaan dalam sistem penghantaran tenaga elektrik. Dengan menggunakan prinsip induksi elektromagnetik, transformer dapat meningkatkan atau merendahkan voltan dan arus elektrik. Ini membolehkan tenaga elektrik dihantar dengan lebih efisien melalui jarak yang lebih jauh tanpa banyak kehilangan tenaga. Dengan mengubah beza keupayaan, transformer memastikan bahawa tenaga elektrik disampaikan dengan tepat dan sesuai dengan keperluan pengguna.