In a mathematical sense, the curvature is the reciprocal of the radius, so that a smaller curvature implies a large radius. A curve of large radius, as for a railway, cannot be laid out by using the radius directly. We will see how the problem of laying out a curve of large radius is solved.
In 1983, Motorola released its first commercial mobile phone, known as the Motorola DynaTAC 8000X. The handset offered 30 minutes of talk-time, six hours standby, and could store 30 phone numbers. It also cost Â£2639 ($3995). In the very early days of the mobile space handsets werenât designed with consumers in mind.
But there were cell phones. Well, one anyway. On April 3, 1973, from a Manhattan street corner -- 6th Ave. between 53rd and 54th -- Motorolaâs Martin Cooper placed the worldâs first mobile phone call. To his rival, no less.