Question

If the planet moves faster when it is closer to the sun and slower when it is farther away, its instantaneous aerial velocity should change. Then how is it that the keplers second law of planetary motion state that the aerial velocity is constant?

Answer 1

Actually in classical mechanics, areal velocity (also called sector velocity or sectorial velocity) is the rate at which area is swept out by a particle as it moves along a curve.


also KEPLER’S SECOND LAW DESCRIBES THE WAY AN OBJECT’S SPEED VARIES ALONG ITS ORBIT

A planet’s orbital speed changes, depending on how far it is from the Sun. The closer a planet is to the Sun, the stronger the Sun’s gravitational pull on it, and the faster the planet moves. The farther it is from the Sun, the weaker the Sun’s gravitational pull, and the slower it moves in its orbit.




since orbital velocity or orbital speed changes according to distance with sun hence arial velocity remains constant