Question

Figure shows the orbit of a planet P round the sun S. AB and CD are the minor and major axes of the ellipse. If U is the potential energy and K is kinetic energy, then |U| > |K| at :

• A. only D
• B. only C
• C. both D & C
• D. neither D nor C

Answer 1

The correct option is C both D & C

At any point$,P.E.=\frac{-GMm}{a}$ and

$K.E.=\frac{GMm}{2a}$.

Now $|P.E.|=\frac{GMm}{a}$ and $|K.E.|=\frac{GMm}{2a}$

We can clearly observe that $|P.E.|=2|K.E.|\Rightarrow |U|>|K|$ at D and C.