4. A chandelier brightens a ballroom after a waiter moves a switch

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

"an open tank has the shape of a right circular cone. the tank is 6 feet across the top and 5 feet high. how much work is done in emptying the tank by pumping the water over the top edge? note: the density of water is 62.4 lbs per cubic foot."

Which of these is not a possible type of energy transformation? a. electrical energy into light energy b. sound energy into nuclear energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy