Nursing Elites

1. A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?

• A. It has a constant centripetal acceleration
• B. Its tangential velocity remains constant
• C. It experiences a force directed towards the center of the circle
• D. It covers the same distance in equal time intervals along its circular path

Correct answer: B

Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.

2. What is the definition of work in physics?

• A. Force applied to an object at rest
• B. Force exerted by an object in motion
• C. Transfer of energy through motion along a direction
• D. Measure of an object's potential energy

Correct answer: C

Rationale: In physics, work is defined as the transfer of energy through motion along a direction. When a force is applied to an object, and the object moves in the direction of the force, work is done on the object. The work done is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Choices A and B do not fully capture the essence of work, as work is about energy transfer through motion, not merely applying force to objects at rest or in motion. Choice D is incorrect as work is not a measure of an object's potential energy; rather, it is the transfer of energy through motion.

3. What is the role of the diaphragm in the respiratory system?

• A. To regulate blood pressure
• B. To contract and expand the lungs
• C. To produce red blood cells
• D. To absorb oxygen

Correct answer: B

Rationale: The correct answer is B: To contract and expand the lungs. The diaphragm plays a crucial role in the respiratory system by contracting and expanding the lungs. When it contracts, it flattens, increasing the volume of the thoracic cavity and causing air to be drawn into the lungs. Conversely, when it relaxes, it moves back up, decreasing the thoracic cavity volume and pushing air out of the lungs. This process is essential for breathing and the exchange of oxygen and carbon dioxide in the body. Choices A, C, and D are incorrect. The diaphragm is not involved in regulating blood pressure, producing red blood cells, or absorbing oxygen. Its primary function is to aid in respiration by facilitating breathing through its contraction and relaxation movements.

4. What is the sensory threshold?

• A. The smallest amount of stimulus required for an individual to feel a sensation
• B. The amount of stimulus required for an individual to feel pain
• C. The amount of stimulus required to cause an individual to move away from the stimulus
• D. The place from which the stimulus is coming

Correct answer: A

Rationale: The sensory threshold refers to the smallest amount of stimulus required for an individual to perceive or feel a sensation. It is the minimum level of stimulus intensity that is detectable by an individual. Choice B is incorrect because the sensory threshold is not specifically related to feeling pain but rather to perceiving any sensation. Choice C is incorrect as the sensory threshold is about perception and not necessarily physical reaction. Choice D is incorrect as it describes the source of the stimulus, not the threshold for perception.

5. When is work done on an object?

• A. Only when the object's velocity changes
• B. Only when a force is applied to the object
• C. Whenever there is a force exerted on the object causing displacement
• D. Only when the object is lifted vertically

Correct answer: C

Rationale: Work is done on an object whenever a force causes displacement in the object's position. According to the work-energy principle, work is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Therefore, work can occur whenever there is a force exerted on the object resulting in displacement, regardless of whether the object's velocity changes or it is lifted vertically. Choice A is incorrect because work can be done even without a change in velocity. Choice B is incorrect as work requires both force and displacement, not just the application of force. Choice D is incorrect because work is not limited to vertical lifting; it can happen in any direction as long as there is a force causing displacement.

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