Though human beings have been able to fly hundreds of thousands of miles into outer space, getting inside the earth has proven much extra difficult. The deepest mines ever drilled are only regarding 10miles deep. To illustrate the difficulties associated with such drilling, Think about the following: The density of steel is about7900 KG per cubic meter, and its breaking stress, defined as the maximum stress the material can bear without deteriorating, is about 2.0 \times 10^9 pascals. What is the maximum length of a steel cable that can be lowered into a mine? Suppose that the magnitude of the acceleration due to gravity remains constant at 9.8 meters per second per second.