Sea level Definition and 52 Threads

What is "Sea Level"? What is "Sea Level" as used in describing the height of a mountain?

Yes, this is in regards to my first question. A weight of 15 lbs at sea level is suspended by a wire rope that does not stretch. The weight is lifted 1 ft and dropped 1 ft. the initial velocity is "zero". What is the peak lb load on the wire when the weight stops falling? Thanks for your...