Nokea
An object is initially at rest. Which of the following will definitely NOT cause it to move?
- A. A constant force acting on it
- B. No force acting on it
- C. A force that increases in magnitude over time
- D. A force that decreases in magnitude over time
Correct Answer: B
Rationale: The correct answer is B because if an object is initially at rest and no force is acting on it, it will remain at rest due to Newton's First Law of Motion. This law states that an object at rest will stay at rest unless acted upon by an external force. Choices A, C, and D all involve forces acting on the object, which would cause it to move according to Newton's laws of motion. Choice A, a constant force acting on the object, would cause it to move at a constant velocity. Choice C, a force that increases in magnitude over time, would accelerate the object. Choice D, a force that decreases in magnitude over time, would decelerate the object.
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Which property of a substance measures the amount of matter per unit volume?
- A. Density
- B. Mass
- C. Weight
- D. Volume
Correct Answer: A
Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of the substance by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Density specifically quantifies how tightly packed the matter in a substance is, providing a measure of compactness or concentration of matter. Therefore, the correct answer is A, Density.
Which process allows for the movement of large molecules, such as proteins and polysaccharides, across the cell membrane?
- A. Endocytosis
- B. Exocytosis
- C. Active transport
- D. Facilitated diffusion
Correct Answer: A
Rationale: Endocytosis is the process by which cells engulf large molecules or particles by wrapping the cell membrane around them to form a vesicle that is brought into the cell. This mechanism facilitates the movement of large molecules like proteins and polysaccharides across the cell membrane. Exocytosis involves the release of large molecules or particles from the cell, opposite to the scenario described in the question. Active transport requires energy to move molecules against their concentration gradient and is not primarily used for transporting proteins and polysaccharides. Facilitated diffusion entails the movement of molecules aided by transport proteins but is not the primary mechanism for transporting large molecules such as proteins and polysaccharides.
Which of the following is a unit of measurement for energy?
- A. Watt (W)
- B. Joule (J)
- C. Newton (N)
- D. Kilogram (kg)
Correct Answer: B
Rationale: The unit of measurement for energy is the Joule (J). Energy is defined as the capacity to do work or produce heat, and the Joule is the standard unit used to measure energy in the International System of Units (SI). A Watt (A) is a unit of power, measured in joules per second, Newton (C) is a unit of force, and Kilogram (D) is a unit of mass. The Joule (J) is the appropriate unit for quantifying energy, making it the correct answer in this context.
What does antidiuretic hormone (ADH) help the kidneys regulate?
- A. Acid-base balance
- B. Blood pressure
- C. Urine output by controlling water reabsorption
- D. All of the above
Correct Answer: C
Rationale: Antidiuretic hormone (ADH) helps the kidneys regulate urine output by controlling water reabsorption. ADH acts on the kidneys to increase the reabsorption of water, leading to a decrease in urine output. This helps the body conserve water and maintain proper fluid balance. ADH primarily affects urine output by controlling water reabsorption and does not directly regulate acid-base balance or blood pressure. Therefore, choices A and B are incorrect because ADH does not directly influence acid-base balance or blood pressure.
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.