Nursing Elites

1. When two cars with different masses collide head-on, which car experiences a greater change in momentum?

• A. The car with the larger mass
• B. The car with the smaller mass
• C. Both cars experience the same change in momentum
• D. It depends on the initial velocities of the cars

Correct answer: C

Rationale: In a head-on collision between two cars, the law of conservation of momentum states that the total momentum of the isolated system remains constant before and after the collision. The change in momentum of one car is equal in magnitude but opposite in direction to the change in momentum of the other car. As a result, both cars experience the same change in momentum during the collision. Choice A is incorrect because the change in momentum is the same for both cars due to the conservation of momentum principle. Choice B is incorrect as the smaller mass car does not experience a greater change in momentum. Choice D is incorrect as the initial velocities of the cars do not determine which car experiences a greater change in momentum; it is solely dependent on the masses of the colliding cars.

2. What type of energy is stored in food?

• A. Mechanical energy
• B. Kinetic energy
• C. Chemical potential energy
• D. Thermal energy

Correct answer: C

Rationale: Food stores energy in the form of chemical potential energy. This energy is released during digestion and metabolism to provide the body with the energy it needs to function. It is derived from the bonds within the molecules of food, such as carbohydrates, fats, and proteins. Choice A, mechanical energy, is incorrect as food does not store energy in the form of mechanical energy. Choice B, kinetic energy, is incorrect as kinetic energy is associated with the motion of objects, not stored in food. Choice D, thermal energy, is incorrect as thermal energy relates to heat energy, which is not the primary form of energy stored in food.

3. Which structure in the respiratory system is responsible for gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchi
• D. Diaphragm

Correct answer: B

Rationale: The alveoli in the lungs are responsible for gas exchange. Alveoli have a rich blood supply and thin walls, enabling the exchange of oxygen and carbon dioxide. Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses out. The trachea functions as an air passage, bronchi are the main airways into the lungs, and the diaphragm is the primary muscle involved in breathing by aiding in lung expansion and contraction, but they are not directly responsible for gas exchange like the alveoli.

4. Which of the following constituents of blood is a biconcave disc that is round and flat without a nucleus?

• A. Plasma
• B. Platelet
• C. RBC
• D. WBC

Correct answer: C

Rationale: The correct answer is C, RBC (Red Blood Cell). Red blood cells are biconcave discs that lack a nucleus, allowing them to carry oxygen efficiently. Plasma (A) is the liquid component of blood that carries various substances. Platelets (B) are cell fragments important for blood clotting. White blood cells (WBCs) (D) are part of the immune system and have a nucleus.

5. What happens during a physical change in matter?

• A. A new substance with different properties is formed
• B. The chemical composition of the substance changes
• C. The original substance can be recovered by physical means
• D. Energy is either released or absorbed

Correct answer: C

Rationale: During a physical change in matter, the original substance undergoes a change in its physical state or appearance without any change in its chemical composition. This means that the original substance can be recovered by physical means, such as melting, freezing, boiling, or condensing. No new substance is formed (option A), the chemical composition remains the same (option B), and energy changes can occur but are not a defining characteristic of a physical change (option D). The ability to recover the original substance by physical means distinguishes physical changes from chemical changes.

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