Kepler's Laws & Planetary Motion
A planet revolving in elliptical orbit has:
A. a constant velocity of revolution.
B. has the least velocity when it is nearest to the sun.
C. its areal velocity is directly proportional to its velocity.
D. areal velocity is inversely proportional to its velocity.
E. to follow a trajectory such that the areal velocity is constant.
Choose the correct answer from the options given below:
Show answer and solution
Answer: (b)
- A: speed changes along the ellipse: wrong.
- B: speed is least when farthest (aphelion), not nearest: wrong.
- C, D: areal velocity is constant, not proportional to speed: wrong.
- E: areal velocity is constant (Kepler's second law): correct.
- So the answer is (b) E only.