alleryStart learning →How is the eccentricity of an ellipse calculated?
AThe focus-to-center distance divided by the semi-major axis
BThe semi-major axis divided by the focus-to-center distance
CThe semi-major axis multiplied by the semi-minor axis
DThe semi-minor axis divided by the semi-major axis
Answer & Solution
Correct answer: A. The focus-to-center distance divided by the semi-major axis
1. Eccentricity e is defined as e = f / a.
2. Here f is the distance from the ellipse's center to a focus, and a is the semi-major axis.
3. An eccentricity of zero, where the focus sits at the center, describes a circle.
_Source: OpenStax Physics (CC BY 4.0), Ch 7 "Newton's Law of Gravitation", section 7.1 Kepler's Laws of Planetary Motion_
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