Stored energy is energy that is saved and can be used later. Which statement is NOT true about stored energy?
A. Batteries can store electrical energy or solar energy.
B. Plants can store energy from the sun.
C. Animals can store energy as fat.
D. Stored energy does not happen naturally.

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.