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Two planets, A and B are orbiting a common star in circular orbits of radii RA and RB, respectively, with RB=2RA. The planet B is 4 2 times more massive than planet A. The ratio ( LBLA ) of angular momentum (LB) of planet B to that of planet A (LA) is closest to integer .
8
Gravity gives the centripetal force: v= GMr ⇒ L=mvr=m GMr
[figure]
LBLA= mBmA RBRA=4 2 2
∴ =8
Answer: 8
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