A tennis ball hangs from the ceiling. You have a gun that shoots tennis balls

 A satellite orbits the Earth in an elliptical (cigar shaped) orbit. What can we say about it?
   A --the satellite is in mechanical equilibrium
   b--ΣF = 0
   c---ΣF ≠ 0
   d---the satellite is in dynamic equilibrium


 A tennis ball hangs from the ceiling. You have a gun that shoots tennis balls mounted on a table where it is 8 feet lower than and off to the side of the hanging tennis ball. If you aim your gun directly at the hanging tennis ball and pull the trigger at the same time that the hanging tennis ball starts to fall, the tennis ball ejected from the gun, neglecting air resistance:
   a--will pass above the tennis ball that is falling from the ceiling
   b---will pass below the tennis ball that is falling from the ceiling
   c---will pass to the side of the tennis ball that is falling from the ceiling
   d---will hit the tennis ball that is falling from the ceiling