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: A

Rationale: In an inelastic collision like this, kinetic energy is not conserved, but momentum is. Since the total momentum before the collision was zero (equal and opposite velocities), it must be zero after the collision as well, resulting in both objects stopping.

2. T cells in the immune system can be categorized into different types. What type of T cell directly kills infected body cells?

• A. Helper T cells
• B. Cytotoxic T cells
• C. Regulatory T cells
• D. Memory T cells

Correct answer: B

Rationale: Cytotoxic T cells directly kill infected body cells. These T cells recognize and destroy cells that are infected with viruses or other pathogens. They are crucial for eliminating threats within the body. Helper T cells, on the other hand, assist in coordinating the immune response by activating other immune cells. Regulatory T cells help maintain immune tolerance and prevent autoimmune reactions. Memory T cells are responsible for 'remembering' specific pathogens to mount a faster and stronger immune response upon re-exposure. Therefore, cytotoxic T cells are the correct answer as they directly target and kill infected cells.

3. A car accelerates from rest. What happens to its kinetic energy and work done on it?

• A. Both kinetic energy and work done increase
• B. Kinetic energy increases, but work done remains constant.
• C. Work done increases, but kinetic energy remains constant.
• D. Both kinetic energy and work done remain constant.

Correct answer: A

Rationale: During acceleration, the car's speed increases, leading to rising kinetic energy. Simultaneously, the force applied to accelerate the car does work on it, increasing the work done.

4. Which type of carbohydrate is the main component of the cell wall in plant cells?

• A. Starch
• B. Glucose
• C. Cellulose
• D. Chitin

Correct answer: C

Rationale: The correct answer is C: Cellulose. Cellulose is a structural polysaccharide and the main component of the cell wall in plant cells. Starch, option A, is a storage polysaccharide found in plants, while glucose, option B, is a simple sugar and a basic unit of carbohydrates, not the main component of plant cell walls. Chitin, option D, is a structural polysaccharide found in the exoskeletons of arthropods and fungal cell walls, not in plant cell walls. Understanding the unique composition of plant cell walls helps in differentiating the types of carbohydrates present in various cellular structures.

5. Positron emission tomography (PET) scans utilize a key property of positrons for medical imaging. What is this property?

• A. High mass
• B. Positive charge
• C. Extreme stability
• D. Identical behavior to electrons

Correct answer: B

Rationale: The correct answer is B: 'Positive charge.' Positron emission tomography (PET) scans rely on the fact that positrons are positively charged particles. When a positron is emitted during radioactive decay, it quickly collides with an electron, resulting in annihilation and the release of two gamma rays in opposite directions. These gamma rays are detected by the PET scanner to create detailed images of the body's internal organs and tissues. The positive charge of positrons is crucial for this process to occur, making option B the correct choice.

6. Salts are formed by the reaction between:

• A. Two acids
• B. An acid and a base
• C. Two bases
• D. A metal and a nonmetal only

Correct answer: B

Rationale: Salts are ionic compounds formed by the reaction of an acid and a base

Similar Questions