Nursing Elites

1. Two objects with equal masses collide head-on, both initially moving at the same speed. After the collision, they stick together. What is their final velocity?

• A. Zero
• B. Half their initial velocity
• C. Their initial velocity
• D. Twice their initial velocity

Correct answer: C

Rationale: In an inelastic collision where two objects stick together after colliding, momentum is conserved. Since the two objects have equal masses and equal initial velocities but opposite directions, their momenta cancel out. Therefore, after the collision, the combined mass will move at the same speed as the initial velocity, but in the direction of one of the objects. Choice A ('Zero') is incorrect because momentum is conserved, and the objects must move after the collision. Choice B ('Half their initial velocity') is incorrect as the final velocity is the same as the initial velocity due to momentum conservation. Choice D ('Twice their initial velocity') is incorrect as the final velocity cannot be twice the initial velocity based on the conservation of momentum principle.

2. The above experimental design description is an example of which of the following types of experiments?

• A. field experiment
• B. natural experiment
• C. controlled experiment
• D. observational study

Correct answer: C

Rationale: The above experimental design description involves the manipulation of an independent variable (light exposure) to observe its effects on the dependent variable (plant growth) under controlled conditions. In a controlled experiment, researchers actively manipulate one or more variables while keeping all other variables constant to establish cause-and-effect relationships. Choice A, a field experiment, typically takes place in a real-world setting but still involves manipulation and control of variables. Choice B, a natural experiment, involves observing naturally occurring differences in variables without researcher intervention. Choice D, an observational study, does not involve manipulation of variables, making it different from the described experimental design.

3. What happens to the potential energy of an object as it falls freely near the Earth's surface?

• A. Potential energy decreases
• B. Potential energy increases
• C. Potential energy remains constant
• D. Potential energy becomes zero

Correct answer: A

Rationale: As an object falls freely near the Earth's surface, its potential energy decreases. This decrease occurs because the gravitational potential energy is being converted into kinetic energy as the object accelerates due to gravity. According to the law of conservation of energy, the total mechanical energy (the sum of potential and kinetic energy) remains constant in the absence of non-conservative forces like air resistance. Choice B ('Potential energy increases') is incorrect because the object's potential energy is being converted into kinetic energy, leading to a decrease. Choice C ('Potential energy remains constant') is incorrect as the conversion of potential energy to kinetic energy results in a decrease in potential energy. Choice D ('Potential energy becomes zero') is incorrect because potential energy is not reduced to zero but is transformed into kinetic energy as the object falls.

4. Which type of symbiosis benefits both organisms from the interaction?

• A. Mutualism
• B. Commensalism
• C. Parasitism
• D. Predation

Correct answer: A

Rationale: The correct answer is 'Mutualism.' Mutualism is a type of symbiosis where both organisms involved benefit from the interaction. This relationship is characterized by cooperation and mutual support, leading to advantages for both parties. In mutualistic relationships, each organism provides something that the other needs, resulting in a mutually beneficial outcome. In contrast, 'Commensalism' (choice B) involves one organism benefiting while the other is unaffected, 'Parasitism' (choice C) benefits one organism at the expense of the other, and 'Predation' (choice D) benefits the predator while harming the prey. Examples of mutualism include the relationship between bees and flowers (pollination) and the partnership between nitrogen-fixing bacteria and leguminous plants.

5. Which property of matter refers to the measure of the force of gravity acting on an object?

• A. Mass
• B. Weight
• C. Density
• D. Volume

Correct answer: B

Rationale: The correct answer is 'Weight.' Weight is the measure of the force of gravity acting on an object. Mass refers to the amount of matter in an object, density is the mass per unit volume of a substance, and volume is the amount of space an object occupies. In this context, the question specifically asks for the property related to the force of gravity, making 'Weight' the correct choice. 'Mass' is the measure of the amount of matter in an object, 'Density' is the mass per unit volume of a substance, and 'Volume' is the space occupied by an object, none of which directly measure the force of gravity on an object.

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