Question

A planet revolves around the sun in an elliptical orbit. If are the velocities of the planet at the perigee and apogee respectively, then the eccentricity of elliptical orbit is given by

• A.
• B. $\frac { v _ { a } - v _ { p } } { v _ { a } + v _ { p } }$
• C. $\frac { v _ { p } + v _ { a } } { v _ { p } - v _ { a } }$
• D. $\frac { v _ { p } - v _ { a } } { v _ { p } + v _ { a } }$

Answer 1

Answer: (D)

$\frac { v _ { p } - v _ { a } } { v _ { p } + v _ { a } }$

Answer 2

As

Where a is semi-major axis of the ellipse