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# A planet moves in an elliptical orbit with sun at one of its focii 1) In path QRP work done by gravity is positive . 2) In path PSQ work done by gravity is negative . 3) Linear velocity of rotation from Q to P via R decreases. 4) Gravitational potential energy increases in going from P to Q via R

a) 1,2 and 3 are correct b) 1,2 and 4 are correct c) 2,3,4 are correct d) 1,2,4 are correct

In path QRP we are going nearer to the sun. Therefore work is done by the gravity workdone is positive
In path PSQ we are going away from the sun, so work done by the gravity is negative
Gravitational potential energy is a negative quantity thus as we move away from the sun it increases.
The linear velocity $\alpha \large\frac{1}{radius}$
As we move from Q and P radius decreases so velocity increases.
So 1,2, and 4 are correct
Hence c is the correct answer.
edited Jul 2, 2014