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.
Dr. Martin Cooper is the person credited with both inventing the modern cell phone as well as making the first cell phone call in New York City, New York in April 1973. A related invention is the cave radio phone invented by Nathan Stubblefield who was awarded a patent for the idea in the early 20 th Century (1908).Since his work does not provide the technology behind modern cell phones, he is not given credit for inventing the cell phone. related invention is the cave radio phone invented by Nathan Stubblefield who was awarded a patent for the idea in the early 20 th Century (1908). Since his work does not provide the technology behind modern cell phones, he is not given credit for inventing the cell phone.