Two balls are moving on a pool table in which total momentum = 0 What can you conclude about the total kinetic energy of the two balls?

A The total kinetic energy must be less than the total potential energy.
B The total kinetic energy must be greater than the momentum of either ball.
C The total kinetic energy must be zero.
D You can't conclude anything about the total kinetic energy.

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.