Nursing Elites

1. When two objects with different masses collide, what happens to their momentum after the collision?

• A. Increases for both objects
• B. Decreases for both objects
• C. Remains the same for both objects
• D. Can increase for one and decrease for the other

Correct answer: C

Rationale: When two objects with different masses collide, their total momentum remains the same after the collision according to the law of conservation of momentum if no external forces are acting on them. This means that the momentum of each individual object may change, but the sum of their momenta will remain constant. Choice A is incorrect because the total momentum of the system is conserved. Choice B is incorrect because momentum is conserved in an isolated system. Choice D is incorrect as it implies a violation of the law of conservation of momentum, which states that the total momentum of an isolated system remains constant.

2. Which of the following enzymes unwinds the double-stranded DNA during replication?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

3. Which of the following blood vessels carries oxygenated blood from the lungs back to the left atrium of the heart?

• A. Pulmonary artery
• B. Pulmonary vein
• C. Aorta
• D. Inferior vena cava

Correct answer: B

Rationale: The correct answer is B: Pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs back to the left atrium of the heart. This oxygenated blood is then pumped out to the rest of the body. The pulmonary artery, choice A, carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta, choice C, is responsible for carrying oxygenated blood from the heart to the body's tissues. Choice D, the inferior vena cava, transports deoxygenated blood from the lower body back to the heart.

4. Which hormone is released by the ovaries to mature an egg?

• A. Estrogen
• B. Luteinizing Hormone
• C. Progesterone
• D. Testosterone

Correct answer: A

Rationale: The correct answer is Estrogen (Choice A). Estrogen is produced by the ovaries and is essential for the maturation of eggs. It plays a crucial role in the development of secondary sexual characteristics, regulation of the menstrual cycle, and preparation of the uterus for implantation of a fertilized egg. Luteinizing Hormone (Choice B) is released by the pituitary gland and plays a role in ovulation, not the maturation of eggs. Progesterone (Choice C) is produced by the ovaries after ovulation and is important for preparing the uterus for pregnancy, not maturing eggs. Testosterone (Choice D) is a male sex hormone primarily produced in the testes, and while small amounts are also produced in the ovaries, it is not the hormone responsible for maturing eggs.

5. If the mass of an object remains constant and its velocity doubles, how does its momentum change?

• A. Momentum doubles
• B. Momentum halves
• C. Momentum quadruples
• D. Momentum remains the same

Correct answer: C

Rationale: Momentum is calculated as the product of an object's mass and its velocity. When the mass remains constant and the velocity doubles, the momentum will increase by a factor of 2 (doubling) due to the increase in velocity. Therefore, the momentum will quadruple (2 x 2 = 4) when the velocity doubles. This relationship between momentum and velocity showcases the direct proportionality of momentum to velocity, given a constant mass. Choices A, B, and D are incorrect. Momentum does not simply double or halve when the velocity doubles; it quadruples as it is directly proportional to the velocity. Hence, the correct answer is C, where momentum quadruples in this scenario.

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