Nursing Elites

1. What happens to the gravitational potential energy of an object as it falls freely?

• A. It decreases
• B. It increases
• C. It remains constant
• D. It becomes zero

Correct answer: A

Rationale: The correct answer is A: 'It decreases.' When an object falls freely, its height decreases, resulting in a decrease in gravitational potential energy. The potential energy is converted into kinetic energy as the object accelerates due to gravity. This conversion process continues until the object reaches the ground or its lowest point, where the gravitational potential energy is minimal or zero. Choice B is incorrect because gravitational potential energy decreases, not increases, during free fall. Choice C is incorrect as gravitational potential energy changes due to the change in height. Choice D is incorrect as the gravitational potential energy does not instantly become zero but decreases gradually as the object falls.

2. The process by which two or more species reciprocally influence each other's evolution through selection pressures exerted on one another is called:

• A. Convergent evolution
• B. Divergent evolution
• C. Coevolution
• D. Coevolution

Correct answer: C

Rationale: A) Convergent evolution refers to the process by which unrelated species evolve similar traits due to similar environmental pressures. This does not involve reciprocal influence between species. B) Divergent evolution refers to the process by which two or more related species become more dissimilar over time due to different selection pressures. This also does not involve reciprocal influence between species. C) Coevolution is the process by which two or more species reciprocally influence each other's evolution through selection pressures exerted on one another. This can lead to a close ecological relationship between the species, such as in predator-prey interactions or mutualistic relationships. D) This option is a duplicate of option C.

3. Which hormone is responsible for regulating sleep-wake cycles and is influenced by light exposure?

• A. Melatonin
• B. Cortisol
• C. Estrogen
• D. Glucagon

Correct answer: A

Rationale: The correct answer is A: Melatonin. Melatonin is the hormone responsible for regulating sleep-wake cycles, also known as the circadian rhythm. Its production is influenced by light exposure, with levels increasing in the evening in response to darkness, signaling the body that it is time to sleep. Choice B, cortisol, is a stress hormone and does not directly regulate sleep-wake cycles. Choice C, estrogen, is a sex hormone and is not primarily involved in regulating sleep. Choice D, glucagon, is a hormone that increases blood glucose levels and is not related to sleep-wake cycles.

4. What are the two main types of nuclear decay, and what differentiates them?

• A. Fission and fusion, based on the size of the nucleus
• B. Alpha and beta decay, based on the emitted particle
• C. Spontaneous and induced decay, based on the trigger
• D. Isotope decay and chain reactions, based on the stability of the nucleus

Correct answer: B

Rationale: The correct answer is B. The two main types of nuclear decay are alpha and beta decay, which are differentiated based on the emitted particle. In alpha decay, an alpha particle (consisting of two protons and two neutrons) is emitted from the nucleus, while in beta decay, a beta particle (either an electron or a positron) is emitted. These decay types are distinguished by the particles they emit, not by the size of the nucleus, trigger, or stability of the nucleus. Choices A, C, and D are incorrect because fission, fusion, spontaneous, induced, isotope decay, and chain reactions are different processes in nuclear physics and do not represent the two main types of nuclear decay based on emitted particles.

5. At the peak of its trajectory, what force is acting on a ball thrown upwards?

• A. Gravity only
• B. Gravity and air resistance only
• C. Neither gravity nor air resistance
• D. All of the above

Correct answer: A

Rationale: At the peak of its trajectory, the ball momentarily stops moving upwards before it starts to fall back down. At this point, the only force acting on the ball is gravity, pulling it back towards the ground. Air resistance is negligible at the peak of the trajectory as the ball is momentarily stationary. Therefore, the correct answer is 'Gravity only.' Choices B, C, and D are incorrect. Option B is incorrect because air resistance is minimal when the ball is at its highest point and its velocity is nearly zero. Option C is incorrect as gravity is the only significant force acting on the ball at that instant. Option D is incorrect since air resistance is not a significant factor at the peak of the trajectory.

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