Nokea
What force keeps a car moving along a curved road?
- A. Gravitational force
- B. Normal force from the road
- C. Air resistance
- D. Friction between the tires and the road
Correct Answer: D
Rationale: The correct answer is D: Friction between the tires and the road. When a car travels along a curved road, the friction between the tires of the car and the road provides the necessary centripetal force required to keep the car moving in the curved path. This friction allows the tires to grip the road and prevent the car from sliding off the curve due to inertia or momentum. Choices A, B, and C are incorrect because gravitational force, normal force from the road, and air resistance do not play a significant role in keeping a car moving along a curved road. While these forces may have other effects on the car's motion, they are not the primary force responsible for maintaining the car's trajectory along a curve.
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Which of the following statements is true regarding a supersaturated solution?
- A. It is unstable and tends to crystallize
- B. It contains more solute than it could dissolve
- C. It has a higher concentration than a saturated solution
- D. It is rarely encountered in everyday solutions
Correct Answer: A
Rationale: A supersaturated solution is unstable and tends to crystallize because it contains more solute than it could dissolve at a given temperature. This excess solute is in a metastable state and can precipitate out if disturbed, leading to the formation of crystals. Option B is incorrect because a supersaturated solution does contain more solute than it could normally dissolve, but it becomes unstable due to this excess solute. Option C is incorrect because while a supersaturated solution does have a higher concentration than a saturated solution, the defining characteristic related to its instability is the excess solute. Option D is incorrect as supersaturated solutions can be encountered in various everyday scenarios, such as certain sugar solutions used in cooking or rock candy production.
What is the main function of the kidneys?
- A. To filter waste products from the blood
- B. To produce urine
- C. To regulate blood pressure
- D. To produce hormones that help control blood sugar levels
Correct Answer: A
Rationale: The main function of the kidneys is to filter waste products, excess ions, and water from the bloodstream to form urine, which is then excreted from the body. This process helps maintain the body's internal environment by regulating the balance of electrolytes, fluid volume, and pH levels. While the kidneys do produce urine as a result of filtering the blood, their primary function is to filter waste products rather than solely producing urine. Although the kidneys play a role in regulating blood pressure by controlling blood volume and electrolyte concentration, their main function is waste filtration. While the kidneys do produce hormones like erythropoietin and renin that regulate physiological processes, such as red blood cell production and blood pressure, the main role of the kidneys is waste filtration.
What is the term used to describe the inability of the kidneys to effectively filter waste products from the blood?
- A. Dehydration
- B. Kidney failure
- C. Incontinence
- D. Nephritis
Correct Answer: B
Rationale: Kidney failure is the term used to describe the inability of the kidneys to effectively filter waste products from the blood. Dehydration refers to insufficient fluid intake and not the kidney's filtering function. Incontinence is the loss of bladder control, not related to kidney filtration. Nephritis is the inflammation of the kidneys, not specifically related to the kidneys' inability to filter waste products.
Rusting of iron is an example of
- A. Endothermic reaction
- B. Exothermic reaction
- C. Single displacement reaction
- D. Photochemical reaction
Correct Answer: A
Rationale: The rusting of iron is an endothermic reaction. This means that it absorbs heat from its surroundings to occur. Rusting involves the slow oxidation of iron in the presence of oxygen and water. As energy is absorbed during this process, it is classified as an endothermic reaction. Choice B, an exothermic reaction, releases heat instead of absorbing it, which is not the case in rusting. Choices C and D are unrelated to the process of rusting and do not involve the absorption of heat from the surroundings.
What is the process by which a fertilized egg implants itself in the lining of the uterus?
- A. Fertilization
- B. Implantation
- C. Gestation
- D. Parturition
Correct Answer: B
Rationale: Implantation is the correct answer. It is the process where a fertilized egg attaches itself to the lining of the uterus to establish a pregnancy. Fertilization is the initial step where the sperm and egg fuse to form a zygote. Gestation refers to the period of fetal development within the uterus. Parturition is the process of giving birth and is not related to the implantation of the fertilized egg, which occurs earlier in the reproductive process.