Nursing Elites

1. A caterpillar starts moving at a rate of 14 in/hr. After 15 minutes, it is moving at a rate of 20 in/hr. What is the caterpillar’s rate of acceleration?

• A. 6 in/hr²
• B. 12 in/hr²
• C. 24 in/hr²
• D. 280 in/hr²

Correct answer: C

Rationale: Acceleration is the change in velocity over time. The change in velocity for the caterpillar is 20 in/hr - 14 in/hr = 6 in/hr. Since this change occurred over 15 minutes (or 0.25 hours), the acceleration can be calculated as (6 in/hr) / (0.25 hr) = 24 in/hr². Therefore, the caterpillar's rate of acceleration is 24 in/hr², which corresponds to choice C. Choice A, 6 in/hr², is incorrect as it does not account for the time factor and the correct calculation. Choice B, 12 in/hr², is incorrect as it doubles the correct acceleration value. Choice D, 280 in/hr², is significantly higher than the correct value, indicating a calculation error.

2. A 2,000-kg car travels at 15 m/s. For a 1,500-kg car traveling at 15 m/s to generate the same momentum, what would need to happen?

• A. It would need to accelerate to 20 m/s.
• B. It would need to add 500 kg in mass.
• C. Both A and B
• D. Either A or B

Correct answer: A

Rationale: Momentum is calculated as the product of mass and velocity. Since momentum is conserved in the absence of external forces, for the 1,500-kg car to generate the same momentum as the 2,000-kg car at 15 m/s, it would need to increase its velocity to compensate for the difference in mass. Accelerating to 20 m/s would achieve this without needing to change the mass of the car. Choice B is incorrect because adding mass is not necessary to match momentum in this scenario.

3. Which conclusion can be drawn from Ohm’s law?

• A. Voltage and current are inversely proportional when resistance is constant.
• B. The ratio of the potential difference between the ends of a conductor to current is a constant, R.
• C. Voltage is the amount of charge that passes through a point per second.
• D. Power (P) can be calculated by multiplying current (I) by voltage (V).

Correct answer: B

Rationale: Ohm's law states that the ratio of the potential difference (voltage) between the ends of a conductor to the current flowing through it is a constant. Mathematically, this is represented as V = I x R, where V is voltage, I is current, and R is the constant resistance. Therefore, the correct conclusion that can be drawn from Ohm's law is that the ratio of the potential difference between the ends of a conductor to current is a constant, denoted as R. This relationship is fundamental to understanding the behavior of electrical circuits and the effect of resistance on voltage and current. Choice A is incorrect because Ohm's law actually states that voltage and current are directly proportional when resistance is constant. Choice C is incorrect because voltage is not the amount of charge that passes through a point per second; rather, it is the electric potential energy per unit charge. Choice D is incorrect because although power (P) can be calculated by multiplying current (I) by voltage (V), this is not a conclusion directly drawn from Ohm's law.

4. In a static fluid, pressure (P) at a depth (h) is governed by the hydrostatic equation:

• A. P = ρgh
• B. P = γh
• C. P = μgh
• D. P = bh

Correct answer: A

Rationale: The correct formula for the pressure at a certain depth in a fluid according to the hydrostatic equation is P = ρgh. Here, ρ represents the fluid's density, g is the gravitational acceleration, and h is the depth. This formula shows that pressure increases linearly with the density of the fluid, the acceleration due to gravity, and the depth. Choices B, C, and D are incorrect because they do not accurately represent the relationship between pressure, density, gravitational acceleration, and depth in a static fluid.

5. In open-channel flow, a critical property is the free surface, which refers to the:

• A. Interface between the liquid and the container walls
• B. Interface between the liquid and a surrounding gas
• C. Bottom of the channel
• D. Region of highest velocity within the liquid

Correct answer: B

Rationale: The free surface in open-channel flow refers to the interface between the liquid and the surrounding gas, typically the atmosphere. This interface is critical as it determines the boundary between the liquid flow and the open environment. Option A is incorrect as it refers to the liquid-container wall interface, not the free surface. Option C is incorrect because it represents the bottom of the channel, not the free surface. Option D is incorrect as it describes the region of highest velocity within the liquid, not the free surface. Therefore, the correct choice is B.

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