Nursing Elites

1. When a person pushes a box across the floor, which of the following forces is NOT doing work?

• A. The person's pushing force
• B. The normal force from the floor
• C. The gravitational force on the box
• D. The frictional force between the box and the floor

Correct answer: B

Rationale: The normal force from the floor is perpendicular to the direction of motion of the box, so it does not contribute to the work being done. Work is only done by forces acting in the direction of motion of an object. In this case, the normal force is acting at a right angle to the motion, hence it does not perform any work on the box. The person's pushing force, the gravitational force, and the frictional force are all acting in the direction of motion of the box, so they contribute to the work being done in moving the box across the floor.

2. Two identical balls, one made of clay and the other made of steel, are dropped from the same height. Which ball reaches the ground first, neglecting air resistance?

• A. The clay ball due to its lower density
• B. The steel ball due to its higher density
• C. Both balls reach the ground simultaneously
• D. It depends on the initial velocities of the balls

Correct answer: C

Rationale: In the absence of air resistance, both balls will experience the same acceleration due to gravity (9.8 m/s^2) regardless of their densities or materials. This means that both balls will reach the ground at the same time, assuming they are dropped from the same height simultaneously. The differences in density or material composition do not affect the rate at which objects fall in a vacuum. Therefore, both the clay and steel balls, being identical in shape and starting position, will have the same free-fall acceleration and will hit the ground simultaneously. Choices A and B are incorrect because the density of the materials does not impact the time it takes for objects to fall under gravity alone. Choice D is incorrect as the initial velocities do not play a role in the time taken to fall in a vacuum, where only the acceleration due to gravity affects the motion.

3. What is the external body covering, providing protection and contributing to temperature regulation, composed of?

• A. Muscle tissue
• B. Epithelial tissue (skin)
• C. Bone marrow
• D. Cartilage

Correct answer: B

Rationale: The external body covering, which is the skin, is composed of epithelial tissue. Epithelial tissue serves as a protective barrier against pathogens, chemicals, and physical damage. It also helps regulate body temperature through processes like sweating. Choice A (Muscle tissue) is incorrect as muscles are responsible for movement and not the external body covering. Choice C (Bone marrow) is incorrect as it is a component of the skeletal system and not the external body covering. Choice D (Cartilage) is incorrect as cartilage is a type of connective tissue found in joints and the structure of some body parts, not the external body covering.

4. In which medium does light propagate at its highest speed?

• A. Air
• B. Water
• C. Glass
• D. Diamond

Correct answer: A

Rationale: Light travels at its highest speed in a vacuum. However, among the options provided, air is the closest medium to a vacuum, making it the correct answer. In general, light travels slower in denser mediums due to interactions with atoms and molecules in the medium. Water, glass, and diamond are denser mediums compared to air, causing light to propagate at slower speeds in these materials, hence making them incorrect choices.

5. Neurotransmitters send chemical messages across the gap between one neuron and another through which of the following structures?

• A. Schwann cell
• B. ganglion
• C. synapse
• D. axon

Correct answer: C

Rationale: Neurotransmitters send chemical messages across the gap between one neuron and another through a structure called the synapse. The synapse is a specialized junction where the axon of one neuron meets the dendrite or cell body of another neuron. Neurotransmitters are released from the axon terminal of the presynaptic neuron and travel across the synaptic cleft to bind to receptors on the postsynaptic neuron, transmitting the signal between the two neurons. Choice A, Schwann cell, is incorrect as Schwann cells are responsible for producing myelin sheath around axons in the peripheral nervous system, not for transmitting neurotransmitters between neurons. Choice B, ganglion, is incorrect as ganglia are clusters of nerve cell bodies outside the central nervous system and do not directly participate in the transmission of chemical messages between neurons. Choice D, axon, is incorrect as the axon is a long, slender projection of a neuron that conducts electrical impulses away from the cell body and towards the axon terminals, where neurotransmitters are released into the synapse, but it is not the structure across which neurotransmitters travel to communicate between neurons.

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