Part $2$ is priority. Thanks

Problem $3$:

The uniform sign has a weight of $1500$ lb and is supported by the pipe AB $,$ which has an inner radius of $2\mathrm{.}75$ inches and an outer radius of $3\mathrm{.}00$ inches. If the face of the sign is subjected to a uniform wind pressure of $p=150l\frac{b}{f}{t}^{{?}^{?}}2.$

$(1)$ Determine the state of stress at points C and D $.$ Show the results on a differential volume element located at each of these points. Neglect the thickness of the sign and assume that it is supported along the outside edge of the pipe.

$(2)$ Check the material yielding or not for points C and D $,$ assuming the material yield stress of the pipe is $120$ ksi $.$