Suppose the gravitational force between the earth and moon was turned off and the pull replaced by the tension in a steel cable joining them. Consider the tension in such a cable, and its size. The tensile strength of a steel cable is about 5.0 x 10⁸ N/m² (each square meter cross section can support a 5.0 x 10⁸-newton force). The cross-sectional area would be about that of

 

    a) a bass guitar string.
    b) a typical vertical cable that supports the George Washington Bridge (connecting NJ and NY).
    c) Chicago's Sears Tower.
    d) Manhattan Island, NY.
    e) an area more than that of New York State.