Nursing Elites

1. What is the mathematical expression for work (W)?

• A. W = F / d
• B. W = F x d
• C. W = d / F
• D. W = F^2 x d

Correct answer: B

Rationale: The correct formula for work (W) is given by the equation W = F x d, where F represents force and d represents the displacement in the direction of the force. Work is calculated by multiplying the force applied by the distance over which the force is applied. Choice A (W = F / d) is incorrect as work is not calculated by dividing force by distance. Choice C (W = d / F) is incorrect because work is not calculated by dividing distance by force. Choice D (W = F^2 x d) is incorrect as work is not calculated by squaring the force and then multiplying by distance.

2. The Reynolds number (Re) is a dimensionless quantity used to characterize:

• A. Fluid density
• B. Flow regime (laminar vs. turbulent)
• C. Surface tension effects
• D. Buoyancy force magnitude

Correct answer: B

Rationale: The Reynolds number is a dimensionless quantity used to characterize the flow regime, specifically whether it is laminar (smooth) or turbulent (chaotic). It depends on the velocity of the fluid, its characteristic length (such as pipe diameter), and its viscosity. A low Reynolds number indicates laminar flow, while a high Reynolds number suggests turbulence. Choices A, C, and D are incorrect because the Reynolds number is not related to fluid density, surface tension effects, or buoyancy force magnitude.

3. Why are boats more buoyant in salt water than in fresh water?

• A. Salt decreases the mass of the boats.
• B. Salt increases the volume of the water.
• C. Salt affects the density of the boats.
• D. Salt increases the density of the water.

Correct answer: D

Rationale: Salt increases the density of water, making saltwater more buoyant than freshwater. The higher density of saltwater provides more lift to a boat, enabling it to float more easily compared to in freshwater. Choice A is incorrect because salt does not affect the mass of the boats. Choice B is incorrect as salt does not increase the volume of water. Choice C is incorrect since salt affects the density of water, not the boats themselves. Therefore, the correct answer is that salt increases the density of the water, resulting in boats being more buoyant in salt water than in fresh water.

4. An object has a constant velocity of 50 m/s and travels for 10 s. What is the acceleration of the object?

• A. 0 m/s²
• B. 5 m/s²
• C. 60 m/s²
• D. 500 m/s²

Correct answer: A

Rationale: The acceleration of an object is defined as the rate of change of its velocity. When an object has a constant velocity, it means there is no change in its speed or direction. In this case, the object maintains a constant velocity of 50 m/s for 10 seconds, which implies that there is no change in velocity. Therefore, the acceleration of the object is 0 m/s² as there is no acceleration or deceleration happening. Choices B, C, and D are incorrect because acceleration is the change in velocity over time, and in this scenario of constant velocity, the acceleration is 0 m/s².

5. An electromagnet is holding a 1,500-kg car at a height of 25 m above the ground. The magnet then experiences a power outage, and the car falls to the ground. Which of the following is false?

• A. The car had a potential energy of 367.5 kJ.
• B. 367.5 kJ of potential energy is converted to kinetic energy.
• C. The car retains potential energy of 367.5 kJ when it hits the ground.
• D. The car’s potential energy converts to kinetic energy and then to sound energy.

Correct answer: C

Rationale: When the car falls to the ground, its potential energy is converted to kinetic energy as it accelerates downwards. Upon impact with the ground, the car's kinetic energy is dissipated in various forms, such as sound energy, heat, and deformation energy. Therefore, the car does not retain its initial potential energy of 367.5 kJ when it hits the ground. Choice A is true because the potential energy of the car can be calculated as mgh = 1500 kg * 9.8 m/s^2 * 25 m = 367,500 J = 367.5 kJ. Choice B is true because as the car falls, its potential energy is converted to kinetic energy. Choice D is true as the kinetic energy is eventually dissipated into other forms upon impact.

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