Easy Physics Spm 2019

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.

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.

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.

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.

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.

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.

Explanation
Apabila gelombang dipantulkan, arah perambatan gelombang akan berubah. Frekuensi, amplitud, dan panjang gelombang akan tetap sama.

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.