Since neutron stars consist totally of neutrons, they are extremely massive and have a density that is hard to imagine. A typical radius and mass for a neutron star are 1.95  103 m and 2.60  1028 kg respectively. (a) Determine the density of a neutron star.   kg/m3 (b) Determine the weight (in pounds) of a penny (V = 360 mm3) if it were made from this material. (Assume 1 lb = 4.448 N.)

There is relatively little space between atoms in solids and liquids, so that the average density of an atom is about the same as matter on a macroscopic scale - approximately 10^3 kg/m^3. The nucleus of an atom has a radius of about 10^-5m of that of the entire atom, and conatins nearly all mass of the atom.  a) What is the approximate density, in kilograms per cubic meter, of a nucleus.  b) One possible remnant of a supernova, called a neutron star, can have the density of a nucleus, while being the size of a small city. What would be the raduis, in kilometers, of the neutron star with a mass 10 times that of the Sun? The radius of the Sun is 7*10^8 m and its mass is 1.99*10^30 kg

(a) What is the average density of the sun? (b) What is the av- erage density of a neutron star that has the same mass as the sun but a radius of only 73.199 km? (express your answer in the proper SI unit and without scientific notation)

The "classical" radius of a neutron is about 0.79 fm (1 femtometer = 10-15 m). The mass of a neutron is 1.675×10-27 kg. Assuming the neutron is sphereical,  calculate its density  in kilometer per cubic meter