I want all of them in English

The initial burette reading was $22 \text{ cm}^3$ and the new reading is $56 \text{ cm}^3$.

There are 50 drops dispensed.

2.

To calculate the tension, $T_A$, in string A, we will use the Principle of Moments.

Given data:

• Weight of the plank ($W_p$) = $50 \text{ N}$
• Length of the plank ($L$) = $5 \text{ m}$
• Weight of the block ($W_b$) = $100 \text{ N}$
• String A is $2.0 \text{ m}$ from the left end.
• String B is $1.5 \text{ m}$ from the right end, which is $5.0 \text{ m} - 1.5 \text{ m} = 3.5 \text{ m}$ from the left end.
• The center of the plank (where $W_p$ acts) is $5.0 \text{ m} / 2 = 2.5 \text{ m}$ from the left end.
• The block is placed at the center of the plank, so $W_b$ also acts at $2.5 \text{ m}$ from the left end.

We will choose point B as the pivot to eliminate $T_B$ from the moment calculation.
Distance of $T_A$ from B = $3.5 \text{ m} - 2.0 \text{ m} = 1.5 \text{ m}$.
Distance of $W_p$ from B = $3.5 \text{ m} - 2.5 \text{ m} = 1.0 \text{ m}$.
Distance of $W_b$ from B = $3.5 \text{ m} - 2.5 \text{ m} = 1.0 \text{ m}$.

Sum of clockwise moments equals sum of anticlockwise moments.
Clockwise moments (from $W_p$ and $W_b$) = $(W_p \times \text{distance from B}) + (W_b \times \text{distance from B})$
Anticlockwise moments (from $T_A$) = $T_A \times \text{distance from B}$

3.

If a constant force is applied to an object moving at a constant velocity, the object will accelerate according to Newton's Second Law ($F=ma$). This means its velocity will change. Velocity includes both magnitude (speed) and direction.

Here are two possible changes in the state of motion of the object:

• Speed: The speed of the object will change. It can increase or decrease depending on the direction of the applied force relative to the initial direction of motion.
• Direction: The direction of the object's motion will change. This will particularly happen if the applied force is not parallel to the initial direction of motion.

4.

To calculate the density of the soil, we need the mass of the soil and the volume of the soil.

Given data:

• Mass of empty density bottle ($m_b$) = $23.5 \text{ g}$
• Mass of bottle + soil (half-filled) ($m_{b+s}$) = $62.1 \text{ g}$
• Mass of bottle + soil + water (completely filled) ($m_{b+s+w_1}$) = $98.1 \text{ g}$
• Mass of bottle + water (completely filled) ($m_{b+w_2}$) = $73.5 \text{ g}$

We assume the density of water ($\rho_{water}$) is $1 \text{ g/cm}^3$.

The volume of the soil is the volume of the bottle minus the volume of the water added.

Rounding to three significant figures:

5.

The stability of a body refers to its ability to return to its original position after being slightly displaced. Two factors that affect the stability of a body are:

• Base Area: A larger base area increases stability because it provides a wider support region, making it harder for the center of gravity to move outside the base when tilted.
• Height of the Centre of Gravity: A lower center of gravity increases stability. When the center of gravity is low, a larger tilt is required for the line of action of the weight to fall outside the base, thus making the object more stable.

6.

To calculate the work done by the force, we use the formula for work done when the force is applied at an angle to the direction of motion.

Given:

• Force ($F$) = $10 \text{ N}$
• Angle ($\theta$) = $60^\circ$ to the horizontal
• Distance ($d$) = $5 \text{ m}$

We know that $\cos(60^\circ) = 0.5$.