Potential energy = Mass x Acceleration due to gravity x Height

Acceleration due to gravity is constant, mostly 10 ms^-2.

If the mass is constant, the potential energy will depend on the height of the object.

The greater the height, the greater the potential energy.

In the above diagram, R is the tallest (greatest height), hence its potential energy will be the greatest.

The mechanical advantage of a lever can be calculated as shown below:

The higher the mechanical advantage, the better the machine our work output.

From the formula you will realize that the longer the distance of the effort from the pivot, the higher the mechanical advantage will be since the distance from the load and pivot is fixed (constant).

The distance P will have the highest mechanical advantage, hence that is the best position to apply the force to lift the load.

The primary producers are the beginning of a food chain. They are autotrophs and are most often photosynthetic organisms such as plants, algae, or cyanobacteria. The organisms that eat the primary producers are called primary consumers. Primary consumers are usually herbivores, plant-eaters, though they may be algae eaters or bacteria eaters.

On addition of saliva which contains an amylase to the cooked yam, a starch digesting enzyme (chemical compound that catalyzes the breakdown of starch), the starch gradually converts to sugar (new substance formed).

Water lily is a plant. Plants take in carbon dioxide and produces oxygen during the process of photosynthesis.

DODDER (Plant Parasite)

Humus

Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter. When animals die, their remains add to the litter.

It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil.

Alloy and their compositions

1. Steel → Iron and Carbon
2. Brass → Copper and Zinc
3. Bronze → Copper and Tin

Sulfur dioxide reacts with water to form sulfurous acid (H₂SO₃) as the product.

S0_2(g) + H₂O_(l) → H₂SO_3(l)

The rusting of iron (Fe) is shown by the chemical equation below:

4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃

Difference between adhesive and cohesive force

Cohesive force is the force that attracts molecules of the same substance while Adhesive force is the force that binds molecules of different substances together.

Why water wets glass

Water wets glass and spreads out on it because the adhesive forces between the liquid and the glass are stronger than the cohesive forces within the water.

Density = $\frac{\mathrm{Mass}}{\mathrm{Volume}}$

Density x Volume = Mass

Dividing both sides by Density

Volume = $\frac{\mathrm{Mass}}{\mathrm{Density}}$

Volume = $\frac{\mathrm{0.1kg}}{\mathrm{1\; kg}{\mathrm{m}}^{-3}}$

Volume = 0.1 m³

The surface of the water acts like an elastic skin due to surface tension.

Surface tension is the force or property of a liquid which makes the surface to behave as if it were a stretched elastic skin or membrane.