Solving Density Problems Video Lessons

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# Problem: (a) What is the average density of the sun? (b) What is the average density of a neutron star that has the same mass as the sun but a radius of only 20.0 km?

###### FREE Expert Solution

Density:

$\overline{){\mathbf{\rho }}{\mathbf{=}}\frac{\mathbf{m}}{\mathbf{V}}}$

Volume, V of a sphere:

$\overline{){\mathbf{V}}{\mathbf{=}}\frac{\mathbf{4}}{\mathbf{3}}{\mathbf{\pi }}{{\mathbf{r}}}^{{\mathbf{2}}}}$

(a)

For the sun:

m = 1.99 × 1030 kg, r = 6.96 × 108 m

Volume, V of the sun:

V = (4/3)(π)(6.96 × 108)3 = 1.4123 × 1027 m

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###### Problem Details

(a) What is the average density of the sun?

(b) What is the average density of a neutron star that has the same mass as the sun but a radius of only 20.0 km?