Nursing Elites

1. A 10-kg object moving at 5 m/s has an impulse acted on it causing the velocity to change to 15 m/s. What was the impulse that was applied to the object?

• A. 10 kgâ‹…m/s
• B. 15 kgâ‹…m/s
• C. 20 kgâ‹…m/s
• D. 100 kgâ‹…m/s

Correct answer: D

Rationale: Impulse is the change in momentum of an object. The initial momentum is calculated as 10 kg × 5 m/s = 50 kg⋅m/s, and the final momentum is 10 kg × 15 m/s = 150 kg⋅m/s. The change in momentum (impulse) is 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choices A, B, and C are incorrect because they do not reflect the correct calculation of the impulse based on the change in momentum of the object.

2. What force was applied to the object that was moved if 100 Nâ‹…m of work is done over 20 m?

• A. 5 N
• B. 80 N
• C. 120 N
• D. 2,000 N

Correct answer: A

Rationale: Work is calculated using the formula Work = Force x Distance. Given that 100 Nâ‹…m of work is done over 20 m, we can rearrange the formula to solve for Force. Force = Work / Distance. Plugging in the values, we get Force = 100 Nâ‹…m / 20 m = 5 N. Therefore, the force applied to the object that was moved is 5 N. Choice B (80 N) is incorrect because it doesn't match the calculated force of 5 N. Choice C (120 N) is incorrect as it is higher than the calculated force. Choice D (2,000 N) is incorrect as it is significantly higher than the correct force of 5 N.

3. Which vehicle has the greatest momentum?

• A. A 9,000-kg railroad car traveling at 3 m/s
• B. A 2,000-kg automobile traveling at 24 m/s
• C. A 1,500-kg MINI Coupe traveling at 29 m/s
• D. A 500-kg glider traveling at 89 m/s

Correct answer: D

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. The momentum formula is p = m × v, where p is momentum, m is mass, and v is velocity. Comparing the momentum of each vehicle: A: 9,000 kg × 3 m/s = 27,000 kg·m/s B: 2,000 kg × 24 m/s = 48,000 kg·m/s C: 1,500 kg × 29 m/s = 43,500 kg·m/s D: 500 kg × 89 m/s = 44,500 kg·m/s. Therefore, the glider (500-kg) traveling at 89 m/s has the greatest momentum of 44,500 kg·m/s, making it the correct choice. Options A, B, and C have lower momentum values compared to option D, proving that the 500-kg glider traveling at 89 m/s has the highest momentum among the given vehicles.

4. The first law of thermodynamics is a principle of energy conservation. It states that:

• A. Energy can be created or destroyed.
• B. The total entropy of an isolated system always decreases.
• C. Energy can neither be created nor destroyed, only transferred or transformed.
• D. The temperature of a system is directly proportional to its entropy.

Correct answer: C

Rationale: The first law of thermodynamics states that energy cannot be created or destroyed; it can only be transferred or converted from one form to another, ensuring energy conservation in any system. Choice A is incorrect because it goes against the principle of energy conservation. Choice B is incorrect as it refers to the second law of thermodynamics, which states that the total entropy of an isolated system always increases. Choice D is incorrect because the temperature of a system is not directly proportional to its entropy.

5. In physics, the relationship between acceleration and force is expressed in ___________.

• A. Newton’s first law of motion
• B. Newton’s second law of motion
• C. Newton’s third law of motion
• D. none of Newton’s laws of motion

Correct answer: B

Rationale: The relationship between acceleration and force is expressed in Newton’s second law of motion. This law states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to the object's mass. Mathematically, this relationship is represented as F = ma, where F is the force, m is the mass of the object, and a is the acceleration. Choice A, Newton’s first law of motion, also known as the law of inertia, states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an external force. Choice C, Newton’s third law of motion, states that for every action, there is an equal and opposite reaction, focusing on the interaction between two objects. Choice D is incorrect because the relationship between acceleration and force is indeed described by one of Newton’s laws of motion, specifically the second law.

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