Solve all the 9 questions in English

$$\text{Work Done} = 10 \, \text{N} \times 5 \, \text{m}$$ $$\text{Work Done} = 50 \, \text{J}$$

The work done is $\boxed{\text{50 J}}$.

c) State the unit of work done.
The unit of work done is the $\boxed{\text{Joule (J)}}$.

Question 2:

a) Define the term 'power'.
Power is the rate at which work is done or energy is transferred.

b) A machine does 200 J of work in 5 s. Calculate the power of the machine.

$$\text{Power} = \frac{200 \, \text{J}}{5 \, \text{s}}$$ $$\text{Power} = 40 \, \text{W}$$

The power of the machine is $\boxed{\text{40 W}}$.

c) State the unit of power.
The unit of power is the $\boxed{\text{Watt (W)}}$.

Question 3:

a) Define the term 'energy'.
Energy is the capacity of a system to do work.

b) State two forms of energy.
Two forms of energy are:

1. Kinetic energy
2. Potential energy (or chemical energy, thermal energy, electrical energy, etc.)

c) State the law of conservation of energy.
The law of conservation of energy states that energy cannot be created or destroyed, but it can be transformed from one form to another. The total amount of energy in an isolated system remains constant.

Question 4:

a) Define the term 'kinetic energy'.
Kinetic energy is the energy possessed by an object due to its motion.

b) A car of mass 1000 kg moves with a velocity of 20 m/s. Calculate its kinetic energy.

$$\text{KE} = \frac{1}{2} \times 1000 \, \text{kg} \times (20 \, \text{m/s})^2$$ $$\text{KE} = \frac{1}{2} \times 1000 \, \text{kg} \times 400 \, (\text{m/s})^2$$ $$\text{KE} = 500 \, \text{kg} \times 400 \, (\text{m/s})^2$$ $$\text{KE} = 200000 \, \text{J}$$

The kinetic energy of the car is $\boxed{\text{200000 J}}$.

Question 5:

a) Define the term 'potential energy'.
Potential energy is the energy stored in an object due to its position or state.

b) A stone of mass 2 kg is lifted to a height of 10 m. Calculate its potential energy. (Take g = 10 N/kg)

$$\text{PE} = 2 \, \text{kg} \times 10 \, \text{N/kg} \times 10 \, \text{m}$$ $$\text{PE} = 200 \, \text{J}$$

The potential energy of the stone is $\boxed{\text{200 J}}$.

Question 6:

a) Define the term 'pressure'.
Pressure is the force applied perpendicular to the surface of an object per unit area over which the force is distributed.

b) A force of 50 N acts on an area of 2 m². Calculate the pressure.

$$\text{P} = \frac{50 \, \text{N}}{2 \, \text{m}^2}$$ $$\text{P} = 25 \, \text{Pa}$$

The pressure is $\boxed{\text{25 Pa}}$.

c) State the unit of pressure.
The unit of pressure is the $\boxed{\text{Pascal (Pa)}}$ or $\boxed{\text{N/m}^2}$.

Question 7:

a) Define the term 'density'.
Density is a measure of mass per unit volume of a substance.

b) A block of wood has a mass of 200 g and a volume of 250 cm³. Calculate its density.

$$\text{Density} = \frac{200 \, \text{g}}{250 \, \text{cm}^3}$$ $$\text{Density} = 0.8 \, \text{g/cm}^3$$

The density of the block of wood is $\boxed{\text{0.8 g/cm}^3}$.

c) State the unit of density.
The unit of density is $\boxed{\text{kg/m}^3}$ or $\boxed{\text{g/cm}^3}$.

Question 8:

a) Define the term 'specific heat capacity'.
Specific heat capacity is the amount of heat energy required to raise the temperature of 1 kg of a substance by 1 °C (or 1 K).

b) 500 J of heat energy is supplied to 2 kg of a substance, and its temperature rises by 5 °C. Calculate the specific heat capacity of the substance.

$$Q = mc\Delta T$$

Where $Q$ is heat energy, $m$ is mass, $c$ is specific heat capacity, and $\Delta T$ is the change in temperature.

$$c = \frac{500 \, \text{J}}{2 \, \text{kg} \times 5 \, \text{°C}}$$ $$c = \frac{500 \, \text{J}}{10 \, \text{kg°C}}$$ $$c = 50 \, \text{J kg}^{-1} \text{°C}^{-1}$$

The specific heat capacity of the substance is $\boxed{\text{50 J kg}^{-1} \text{°C}^{-1}}$.

c) State the unit of specific heat capacity.
The unit of specific heat capacity is $\boxed{\text{J kg}^{-1} \text{°C}^{-1}}$ or $\boxed{\text{J kg}^{-1} \text{K}^{-1}}$.

Question 9:

a) Define the term 'latent heat of fusion'.
Latent heat of fusion is the amount of heat energy required to change 1 kg of a substance from a solid state to a liquid state at its melting point without a change in temperature.

b) 100 g of ice at 0 °C melts completely when 33400 J of heat energy is supplied. Calculate the specific latent heat of fusion of ice.

$$Q = mL_f$$

Where $Q$ is heat energy, $m$ is mass, and $L_f$ is the specific latent heat of fusion.

$$L_f = \frac{33400 \, \text{J}}{0.1 \, \text{kg}}$$ $$L_f = 334000 \, \text{J/kg}$$

The specific latent heat of fusion of ice is $\boxed{\text{334000 J/kg}}$.

c) State the unit of specific latent heat of fusion.
The unit of specific latent heat of fusion is $\boxed{\text{J/kg}}$.