Polar Equations of Conics Can Be Used to Describe the Motion

question 9

Multiple Choice

Polar equations of conics can be used to describe the motion of comets. These paths can be graphed using the following polar equation, where e is the eccentricity of the conic and r _per is the perihelion distance measured in AU. For Encke's Comet r _per = 0.3317 and e = 0.8499, determine whether its trajectory is elliptical, parabolic, or hyperbolic. $r = \frac { r _ { \mathrm { per } } ( 1 + e ) } { 1 - e \cos \theta }$

• A) parabolic
• B) elliptical
• C) hyperbolic