The size of the forces between you and the planet you're on is
your weight on that planet.
Don't forget that you pull the planet with a force equal to the force
that the planet pulls on you. Your weight on Earth is the same as
the Earth's weight on you !
When light passes from a faster medium into a slower medium, light will be refracted toward a line drawn perpendicular to the point of refraction. <em>(B)</em>
Yes, that's correct. The note "A" (which is used to tune the other strings of the guitar) corresponds to a frequency of 440 Hz.
