Question

A planet in its elliptical orbit has the farthest distance from the sun($r_1$) equal to three times its nearest distance from the sun($r_2$). Will the orbital speed of the planet be different at those points?

• A. Orbital velocity at nearest point will be twice that at farthest point
• B. Orbital velocity at nearest point will be thrice that at farthest point
• C. Orbital velocity at farthest point will be thrice that at nearest point
• D. Orbital velocity will be same, since no other force acts on the planet

Answer 1

The correct option is B Orbital velocity at nearest point will be thrice that at farthest point

If $v_1$ and $v_2$ are the velocities of the planet at distances $r_1$ and $r_2$, then $m{v}_1{r}_1=m{v}_2{r}_2$ OR $v_2/v_1=r_1/r_2=3$

The correct answer is option (b)