Passage VII

Planets revolve around the Sun in elliptical orbits, as shown in Figure 1.

The eccentricity of an elongated the ellipse describes its elongation; the more elongated the ellipse, the greater its eccentricity. The semimajor axis is half the length of the ellipse.

Perihelion (Angle θ = 0°) is the point on the orbit closest to the Sun; aphelion (θ = 180°) is the point on the orbit farthest the Sun. The speed of a planet varies with θ.The speed of a planet versus θ is shown in Figure 2 for orbits with various eccentricities and semimajor axes.

38. A planet will escape from the solar system if its orbital speed is greater than the escape velocity.
Based on the data in Figure 2, if the semimajor axis is 1.5× 108 km, the eccentricity is 0.10, and the escape velocity at perihelion is 44.2 km/sec, will the planet escape the solar system?

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

Look at the first picture of figure 2, and pay attention to the solid line inside (eccentricity is 0.10). When the planet is in perihelion, that is, when θ is 0° or 360°, the speed is 40.5 km/sec, which is less than the stem of the question The escape velocity given in is 44.2 km/sec, so it will not escape the solar system