Which of the following best explains why an ice skater is able to coast on ice for a long distance without pushing off in a straight line across the ice?
- A. The force of friction on the blades of the skates is greater than the force of friction on the ice.
- B. The force of friction on the blades of the skates is less than the force of friction on the ice.
- C. The ice exerts a constant forward force on the skater.
- D. The buoyant force on the blades of the skates is greater than the weight of the skater.
Correct Answer & Rationale
Correct Answer: B
An ice skater can glide smoothly due to the minimal friction between the skate blades and the ice, which is significantly lower than the friction experienced on other surfaces. This reduced friction allows the skater to maintain momentum over longer distances without needing to push off. Option A is incorrect because it suggests greater friction on the blades, which would hinder movement. Option C is misleading, as the ice does not exert a forward force; instead, the skater continues moving due to existing momentum. Option D is also wrong; while buoyancy affects weight in water, it does not apply to ice skating, where weight and friction are the primary factors.
An ice skater can glide smoothly due to the minimal friction between the skate blades and the ice, which is significantly lower than the friction experienced on other surfaces. This reduced friction allows the skater to maintain momentum over longer distances without needing to push off. Option A is incorrect because it suggests greater friction on the blades, which would hinder movement. Option C is misleading, as the ice does not exert a forward force; instead, the skater continues moving due to existing momentum. Option D is also wrong; while buoyancy affects weight in water, it does not apply to ice skating, where weight and friction are the primary factors.
Other Related Questions
Earth's diameter is approximately 12,700 kilometers. Which of the following layers is located approximately 6,000 kilometers beneath Earth's surface and is composed primarily of iron and nickel?
- A. The core
- B. The crust
- C. The lithosphere
- D. The mantle
Correct Answer & Rationale
Correct Answer: A
The core, located about 6,000 kilometers beneath Earth's surface, is primarily composed of iron and nickel, making it the densest layer of the planet. The crust, option B, is the outermost layer and is much shallower, averaging only about 30 kilometers thick. Option C, the lithosphere, includes the crust and the uppermost part of the mantle, but it does not reach anywhere near 6,000 kilometers deep. The mantle, option D, lies between the crust and the core, extending to about 2,900 kilometers down, but it is primarily composed of silicate minerals, not iron and nickel.
The core, located about 6,000 kilometers beneath Earth's surface, is primarily composed of iron and nickel, making it the densest layer of the planet. The crust, option B, is the outermost layer and is much shallower, averaging only about 30 kilometers thick. Option C, the lithosphere, includes the crust and the uppermost part of the mantle, but it does not reach anywhere near 6,000 kilometers deep. The mantle, option D, lies between the crust and the core, extending to about 2,900 kilometers down, but it is primarily composed of silicate minerals, not iron and nickel.
The rotation of Earth around its axis is responsible for which of the following?
- A. The force of gravity
- B. The day and night cycle
- C. The temperature differences between seasons
- D. The movement of continents relative to one another
Correct Answer & Rationale
Correct Answer: B
The rotation of Earth around its axis creates the day and night cycle, as different parts of the planet face the Sun and then move into its shadow. This explains why we experience daytime and nighttime in a 24-hour period. Option A is incorrect; gravity is primarily caused by Earth's mass, not its rotation. Option C is also wrong; temperature differences between seasons are due to Earth's tilt and its orbit around the Sun, not its rotation. Lastly, option D misrepresents the concept; the movement of continents is influenced by tectonic activity, not the rotation of Earth.
The rotation of Earth around its axis creates the day and night cycle, as different parts of the planet face the Sun and then move into its shadow. This explains why we experience daytime and nighttime in a 24-hour period. Option A is incorrect; gravity is primarily caused by Earth's mass, not its rotation. Option C is also wrong; temperature differences between seasons are due to Earth's tilt and its orbit around the Sun, not its rotation. Lastly, option D misrepresents the concept; the movement of continents is influenced by tectonic activity, not the rotation of Earth.
Based on the food web shown, which of the following is true about the feeding relationships?
- A. Bivalves have no natural predators in the Chesapeake Bay ecosystem.
- B. Wading birds are herbivores that eat aquatic vegetation.
- C. Phytoplankton are producers that convert light energy into organic matter.
- D. Sea ducks are primary consumers that eat only bald eagles.
Correct Answer & Rationale
Correct Answer: C
In the food web, phytoplankton are classified as producers because they perform photosynthesis, converting light energy into organic matter. This foundational role supports the entire ecosystem. Option A is incorrect; bivalves often have predators, such as certain fish and birds, that feed on them. Option B misclassifies wading birds, which are carnivores that primarily feed on small fish and invertebrates, not herbivores. Option D is misleading, as sea ducks are primary consumers but do not exclusively eat bald eagles; they primarily consume aquatic plants and invertebrates. Thus, option C accurately reflects the role of phytoplankton in the ecosystem.
In the food web, phytoplankton are classified as producers because they perform photosynthesis, converting light energy into organic matter. This foundational role supports the entire ecosystem. Option A is incorrect; bivalves often have predators, such as certain fish and birds, that feed on them. Option B misclassifies wading birds, which are carnivores that primarily feed on small fish and invertebrates, not herbivores. Option D is misleading, as sea ducks are primary consumers but do not exclusively eat bald eagles; they primarily consume aquatic plants and invertebrates. Thus, option C accurately reflects the role of phytoplankton in the ecosystem.
Fossilized remains of prehistoric organisms are typically found in which of the following types of rock?
- A. Metamorphic rock
- B. Igneous rock
- C. Sedimentary rock
- D. Molten rock
Correct Answer & Rationale
Correct Answer: C
Fossilized remains are most commonly found in sedimentary rock, which forms from the accumulation of sediment and organic material in layers. This environment allows for the preservation of organisms. Metamorphic rock (A) forms under high pressure and temperature, altering existing rocks and typically destroying fossils. Igneous rock (B) is created from cooled magma or lava, which does not preserve organic material. Molten rock (D) refers to rock in a liquid state, which cannot contain fossils as it is not solidified. Thus, sedimentary rock is the ideal environment for fossil preservation.
Fossilized remains are most commonly found in sedimentary rock, which forms from the accumulation of sediment and organic material in layers. This environment allows for the preservation of organisms. Metamorphic rock (A) forms under high pressure and temperature, altering existing rocks and typically destroying fossils. Igneous rock (B) is created from cooled magma or lava, which does not preserve organic material. Molten rock (D) refers to rock in a liquid state, which cannot contain fossils as it is not solidified. Thus, sedimentary rock is the ideal environment for fossil preservation.