Ok I have 2 related questions Qns1 1. The problem statement, all variables and given/known data Two satellites, A and B, orbiting around Earth have the same kinetic energy. Satellite A has a larger mass than satellite B. Which of the following statements is false? A Satellite A has a larger period. B Satellite A has a larger orbital radius. C Satellite A has a smaller total energy. D Satellite A has a smaller angular velocity. 2. Relevant equations Ok if i'm not wrong we're supposed to use mv^2/r = GMm/r^2? Then v=rw and w=2(pi)/T 3. The attempt at a solution Ok so i was thinking since KE is constant, velocity of A should be smaller than B. Then.. what? Ok v^2/r = GM/r^2, but i'm stuck here cause gravitational acceleration and r can vary. Answer is C btw. Then there is another similar question: Qn2 1. The problem statement, all variables and given/known data Two stars of masses M and 2M move in circular motion about their common centre of mass. Which of the following statements is true? A. Both stars move with the same speed B. Both stars move with the same angular velocity C. Both stars move with the same radius D. Such a motion is not possible. 2. Relevant equations Gravitational field strength = GM/r^2 = v^2/r = rw^2 3. The attempt at a solution No idea really. I thought all of them were untrue. The answer was B. But how can that be possible? Satellites orbit around earth with different angular velocities no? Unless the question is saying that the stars exert some gravitational force on the centre of mass also? If that makes a difference. Oh and i would like to clarify something. What is the condition for a uniform circular motion? Is it that the resultant force must be just enough to provide for the centripetal force?