Question

Within a neutron star, the material at the center has a density of 1.0 x 10 18 kg/m 3 . If a small

sphere of this material of radius 1.0 x 10 -5 m were some how transported to the surface of the
earth, how much would it weigh?

Answer 1

Density of the neutron star is given as

`\rho = 1 \time 10^(18) kg/m^3`

Radius of the star is also given as

`R = 1 * 10^(-5) m`

now in order to find the mass of star we can assume that star is spherical in shape

so here we can use

`V = (4)/(3)\pi R^3`

`V = (4)/(3)\pi (1 * 10^(-5))^3`

`V = 4.2 * 10^(-15) m^3`

now mass of the star will be given as

`M = \rho V = 4.2 * 10^(-15) * 1 * 10^(18)`

`M = 4.2 * 10^3 kg`

so weight of the star on the earth will be

`W = Mg`

`W = 4.2 * 10^3 * 9.8`

`W = 4.1 * 10^4 N`

so weight on the earth is given by above equation