Nokea
What happens to the momentum of an object when there is no external force acting upon it?
- A. Momentum increases
- B. Momentum decreases
- C. Momentum remains constant
- D. Momentum becomes zero
Correct Answer: C
Rationale: When there is no external force acting upon an object, the law of conservation of momentum dictates that the momentum of the object remains constant. This means that the momentum does not increase or decrease; it stays the same. Choice A is incorrect because momentum does not increase. Choice B is incorrect because momentum does not decrease. Choice D is incorrect as momentum does not become zero; it remains constant as per the conservation law. Therefore, the correct answer is C, as the object's momentum is unchanged in the absence of external forces.
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What is the difference between heat and temperature?
- A. They are the same thing.
- B. Heat is a form of energy, while temperature measures the average kinetic energy of particles.
- C. Heat flows from cold to hot, while temperature flows from hot to cold.
- D. Heat is measured in Celsius, while temperature is measured in Joules.
Correct Answer: B
Rationale: Heat and temperature are distinct concepts. Heat is a form of energy that transfers from a higher temperature object to a lower temperature object, while temperature represents the average kinetic energy of particles in a substance. Heat is quantified in units like Joules or calories, whereas temperature is typically gauged in degrees Celsius or Fahrenheit. Therefore, choice B correctly distinguishes between heat and temperature, making it the correct answer. Choices A, C, and D are incorrect because they do not accurately define the difference between heat and temperature. Choice A erroneously suggests they are the same, choice C confuses the direction of heat and temperature flow, and choice D provides inaccurate units for measuring heat and temperature.
What accurately describes the Linnaean system of classification?
- A. It focuses on evolutionary relationships between organisms.
- B. It uses dichotomous keys for identification.
- C. It groups organisms based on shared functions.
- D. It emphasizes a hierarchical ranking system.
Correct Answer: D
Rationale: The Linnaean system of classification, developed by Carl Linnaeus, is based on a hierarchical ranking system where organisms are grouped into categories based on shared characteristics. This system organizes organisms into a hierarchy of increasingly specific categories, from broad to narrow, such as kingdom, phylum, class, order, family, genus, and species. The emphasis on a hierarchical ranking system allows for systematic organization and classification of a wide variety of organisms based on their similarities and differences, making it easier to study and understand the diversity of life forms. Choice A is incorrect because the Linnaean system is not primarily focused on evolutionary relationships but rather on shared characteristics for classification. Choice B is incorrect because dichotomous keys are tools used for identifying organisms, not the fundamental basis of the Linnaean system. Choice C is incorrect as the Linnaean system categorizes organisms based on shared characteristics, not shared functions.
What does the T wave on an ECG correspond to?
- A. Atrial depolarization
- B. Ventricular depolarization
- C. Atrial repolarization
- D. Ventricular repolarization
Correct Answer: D
Rationale: The T wave on an ECG corresponds to ventricular repolarization. Following ventricular depolarization, which is represented by the QRS complex, the ventricles undergo repolarization during the T wave. This phase signifies the recovery of ventricular muscle cells as they prepare for the subsequent depolarization cycle. Choices A, B, and C are incorrect because the T wave specifically reflects the repolarization of the ventricles, not the atria or their respective depolarization or repolarization phases.
What is the primary function of hematopoietic tissue?
- A. Building and repairing bone
- B. Supporting and connecting tissues
- C. Production of blood cells
- D. Contracting for movement
Correct Answer: C
Rationale: The primary function of hematopoietic tissue is the production of blood cells. Hematopoietic tissue, primarily found in the bone marrow, is responsible for generating red blood cells, white blood cells, and platelets. These blood cells are vital for oxygen transport, immune response, and blood clotting. Choices A, B, and D are incorrect as they do not reflect the main function of hematopoietic tissue. Building and repairing bone is primarily carried out by osteoblasts and osteoclasts, supporting and connecting tissues is a role of connective tissues like tendons and ligaments, and contracting for movement is a function of muscle tissue.
What type of force opposes the motion of an object moving through a fluid (liquid or gas)?
- A. Gravitational force
- B. Tension force
- C. Viscous force
- D. Magnetic force
Correct Answer: C
Rationale: When an object moves through a fluid, it experiences resistance due to the viscosity of the fluid. This resistance is known as the viscous force, which opposes the motion of the object. Gravitational force is the force of attraction between two objects with mass, tension force is the force transmitted through a string, and magnetic force is the force exerted by magnets. In the context of an object moving through a fluid, the force opposing its motion is the viscous force because it resists the relative motion of the object through the fluid.