How is heat related to phase changes

An electromagnet is a device in which moving electric chargers in a coil of wire create a magnet. whats one advantage of using electromagnetic in devices

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.

What is the relationship between ozone and smog?