You are traveling in a spaceship from the Earth to Alpha Centauri when exactly half-way there you receive (at the same time) light from explosions on Earth and Alpha Centauri. Explain whether this is or is not one of those occasions when being half-way between the end-points means the events (the explosions) were simultaneous in your coordinate system. Note that this is not a yes/no question. You need to provide a reason

Sound is a disturbance that travels through a medium as a

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

In a good thermo flask the main cause of heat loss is