Y11 SET 6

To convert the Earth's orbital period from days to seconds before calculating the average orbital speed, which of the following methods should you use?

• Multiply 365 days by 24 hours, then by 60 minutes, then by 60 seconds to get the total seconds.

• Divide 365 days by 24 to get the number of seconds.

• Multiply 365 days by 60 to get the number of seconds.

• Add 365 days to 24 hours to get the number of seconds.

Using your understanding of the accretion model for Solar System formation, explain why the four planets nearest the Sun are rocky and small, while the four planets furthest from the Sun are gaseous and large. Which of the following best summarizes the reasoning behind this difference?

• The inner planets formed from heavier elements that could withstand higher temperatures near the Sun, while lighter gases were pushed outward, forming the outer planets.

• The inner planets absorbed more sunlight, making them larger and gaseous, while the outer planets remained small and rocky.

• The outer planets formed first and blocked material from reaching the inner Solar System.

• The Sun’s gravity only affected the outer planets, causing them to become gaseous and large.

When analyzing planetary data, which combination of factors would you use to determine the strength of a planet’s gravitational field at its surface?

• Surface temperature and density.

• Orbital distance and orbital duration.

• Density and uniform gravitational field strength.

• Orbital duration and surface temperature.

Using your understanding of gravitational fields, explain why the strength of the gravitational field at the surface of a planet depends on the mass of the planet, and predict how this would affect the weight of an object on different planets.

• The gravitational field strength is independent of the planet's mass, so the weight of an object remains the same on all planets.

• The gravitational field strength increases with the planet's mass, so an object weighs more on a more massive planet.

• The gravitational field strength decreases with the planet's mass, so an object weighs less on a more massive planet.

• The gravitational field strength only depends on the distance from the Sun, not the planet's mass.

The difference between perihelion and aphelion distances, due to orbital eccentricity, affects the climate or seasons on a planet like Mars by:

• A greater difference causes more extreme seasonal changes due to varying solar energy received.

• A smaller difference leads to more extreme seasons.

• Eccentricity does not affect the climate or seasons.

• A greater difference causes the planet to spin faster, affecting seasons.

To determine which planet is most similar to Earth in terms of gravitational field strength and density, which method should you use?

• Compare the values for gravitational field strength and density for each planet to Earth's values; Venus is most similar.

• Choose the planet with the closest orbital distance to Earth; Mars is most similar.

• Select the planet with the highest surface temperature; Mercury is most similar.

• Pick the planet with the longest orbital duration; Neptune is most similar.

A planet suddenly starts moving slower in its orbit. Based on energy conservation, what does this indicate about its position relative to the Sun?

• The planet is moving closer to the Sun because it is losing energy.

• The planet is moving farther from the Sun because its kinetic energy is decreasing and potential energy is increasing.

• The planet is moving closer to the Sun because its potential energy is increasing.

• The planet is moving farther from the Sun because its total energy is increasing.

Given that nuclear fusion in the Sun’s core requires extremely high temperatures and pressures, explain why these conditions are necessary for fusion to occur, and describe what would happen if the temperature or pressure were significantly lower.

• High temperatures and pressures are needed to overcome the repulsion between positively charged nuclei; if lower, fusion would not occur efficiently.

• High temperatures and pressures are needed to cool the Sun’s core; if lower, fusion would occur faster.

• High temperatures and pressures are needed to separate hydrogen atoms; if lower, the Sun would emit more energy.

• High temperatures and pressures are needed to form water in the Sun’s core; if lower, the Sun would become a black hole.

A scientist wants to estimate the distance to a distant galaxy. Which unit is most useful for expressing such vast astronomical distances?

• Light-year

• Kilometer

• Meter

• Second

Which sequence best describes the life cycle of a star, from its formation to its possible outcomes after exhausting its hydrogen fuel?

• A star forms from interstellar clouds, becomes a protostar, stabilizes, uses up hydrogen, and then may become a red giant or supergiant, eventually forming a white dwarf, neutron star, or black hole.

• A star forms from a planet, becomes a comet, and then explodes into a supernova, leaving behind only dust.

• A star forms from hydrogen atoms, immediately becomes a black hole, and then turns into a planet.

• A star forms from interstellar clouds, becomes a planet, and then cools down to become a comet.