The stability of a body can be increased by lowering its centre of gravity. One way of lowering its centre of gravity is by adding mass to the base of the object.

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7) The stability of a body can be increased by lowering its centre of gravity. One way of lowering its centre of gravity is by adding mass to the base of the object.

8) A high mountain climber is likely to experience nose bleeding because the atmospheric pressure decreases significantly at high altitudes. This lower external pressure creates a larger pressure difference compared to the relatively constant blood pressure inside the body, causing delicate blood vessels in the nose to rupture.

9)

• Why the salt dissolves: Common salt (sodium chloride) is an ionic compound. Water is a polar solvent. The polar water molecules surround and attract the positive sodium ions and negative chloride ions, pulling them apart from the crystal lattice and dispersing them into the water. This process is called hydration.
• Why the water doesn't overflow: Water molecules are not packed perfectly tightly; there are intermolecular spaces between them. When the salt dissolves, its ions occupy these existing spaces between the water molecules, rather than significantly increasing the overall volume of the solution.