In two or more complete sentences, describe two differences between electromagnetic waves and mechanical waves,

Electromagnetic waves travel in vacuum where as mechanical waves don't. The mechanical waves need a medium like water, air, or anything for it to travel. While mechanical waves are cause by wave amplitude and not by frequency, electromagnetic waves are produced by the vibration of the charged particles.

Explanation:

uranium fissions/breaks up giving out energy and neutrons

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.