Question

speed of planet moving in elliptical orbit is doubled when move at apagee. The eccentricity of the orbit is 0.5 Due to inctease in speed its onew orbit will be:-​

Answer 1

Explanation:

Apogee is the farthest position from focus the planet goes to.

Perigee is the nearest position from focus the planet reaches.

From Kepler's law,

T

2

∝R

3

Hence as in this movement from apogee to perigee, R decreases, so T decreases, and hence the speed must increase.

Clearly the distance from focus(Sun) decreases.

Potential energy of system is −

r

GMm

as 'r' decreases, so does the potential energy(since it is negative).

Angular momentum is conserved since there is no external torque acting on the system of Sun and planet.