Nursing Elites

1. Two objects with equal masses collide head-on, both initially moving at the same speed. After the collision, they stick together. What is their final velocity?

• A. Zero
• B. Half their initial velocity
• C. Their initial velocity
• D. Twice their initial velocity

Correct answer: C

Rationale: In an inelastic collision where two objects stick together after colliding, momentum is conserved. Since the two objects have equal masses and equal initial velocities but opposite directions, their momenta cancel out. Therefore, after the collision, the combined mass will move at the same speed as the initial velocity, but in the direction of one of the objects. Choice A ('Zero') is incorrect because momentum is conserved, and the objects must move after the collision. Choice B ('Half their initial velocity') is incorrect as the final velocity is the same as the initial velocity due to momentum conservation. Choice D ('Twice their initial velocity') is incorrect as the final velocity cannot be twice the initial velocity based on the conservation of momentum principle.

2. What is the independent variable in this experiment?

• A. Time
• B. Dog weight
• C. Dog species
• D. Dog food type

Correct answer: D

Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.

3. Which of the following phases of mitosis is characterized by the separation of sister chromatids and their movement to opposite poles?

• A. Metaphase
• B. Anaphase
• C. Telophase
• D. Cytokinesis

Correct answer: B

Rationale: During anaphase of mitosis, the sister chromatids, which are duplicated copies of a chromosome, separate and move towards opposite poles of the cell. This movement is facilitated by the shortening of microtubules attached to the chromatids. As a result, each pole of the cell receives a complete set of chromosomes, ensuring that the daughter cells produced after cell division will have the correct number of chromosomes. Metaphase is characterized by the alignment of chromosomes at the cell's equator, not their separation. Telophase is the phase following anaphase, where the separated chromatids reach the opposite poles and nuclear envelopes start to form around them. Cytokinesis is the final stage of cell division, where the cytoplasm is divided to form two separate daughter cells.

4. When ethanol (Câ‚‚Hâ‚…OH) reacts with sodium metal (Na), what is the product?

• A. Ethene (Câ‚‚Hâ‚„)
• B. Sodium ethoxide (Câ‚‚Hâ‚…ONa)
• C. Ethane (Câ‚‚H₆)
• D. Sodium acetate (CH₃COONa)

Correct answer: B

Rationale: When ethanol (C₂H₅OH) reacts with sodium metal (Na), the product formed is Sodium ethoxide (C₂H₅ONa). This reaction is a classic example of a metal displacing hydrogen in an alcohol to form an alkoxide. In this specific case, sodium replaces the hydrogen in ethanol, resulting in the formation of sodium ethoxide. Choice A, Ethene (C₂H₄), is incorrect as it is a different compound formed from the dehydration of ethanol, not its reaction with sodium. Choice C, Ethane (C₂H₆), is incorrect as it is a saturated hydrocarbon, not the product of the reaction of ethanol with sodium metal. Choice D, Sodium acetate (CH₃COONa), is incorrect as it involves acetic acid, not ethanol, reacting with sodium to form the salt sodium acetate.

5. Which of the following correctly orders the layers of the epidermis from most superficial to deepest?

• A. S. spinosum, S. basale, S. corneum, S. granulosum, S. lucidum
• B. S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale
• C. S. corneum, S. spinosum, S. basale, S. granulosum, S. lucidum
• D. S. basale, S. spinosum, S. granulosum, S. lucidum, S. corneum

Correct answer: B

Rationale: The correct order of the layers of the epidermis from most superficial to deepest is: Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale. Choice B, 'S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale,' provides the accurate layering from the outermost to the innermost layer of the epidermis. Choice A is incorrect as it starts with Stratum spinosum, which is not the most superficial layer. Choice C is incorrect as it places Stratum spinosum before Stratum basale. Choice D is incorrect as it starts with Stratum basale, which is the deepest layer of the epidermis.

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