Amajor benefit of the daguerreotype process is that

Daguerreotype is defined as the first practical photographic process which was introduced in Paris on January 7, 1839. To make the image permanent, Daguerre used salt solution. The result of his introduced process is a finely defined image with surface which is delicate. The major benefit of daguerreotype is if the images are correctly preserved, the pictures could last forever. Aside from this, since it produces superior quality of outline, it is thus suitable for portraitures. 

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

a.   mass number from atomic number