Based on Kepler's work, which best describes the orbit If a planet around the Sun? a circle with the Sun at the very center
an ellipse with the Sun at the very center
a circle with the Sun at one edge
an ellipse with the Sun at one focus

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.