Density of the sun as a white dwarf.

[Bottomsouth]

Homework Statement

In about 5 billion years, at the end of its lifetime, our sun will end up as a white dwarf, having about the same mass as it does now, but reduced to about 15,000 km in diameter.What will be its density at that stage?

g/cm^3

Homework Equations

D=m/v
4/3(3.14)r^3

The Attempt at a Solution

Sun's mass is Sun's mass is = 1.99 x 10^30 kg
kg to g = 1.99 x 10^33
v = 7500 km to 750,000,000 centimeter

D = 1.99 x 10^33 / (4/3)(3.14)(7.5 x 10^33)^3 = 1.12 x 10^54 ?

Is this correct? I have been getting it wrong each time I input the answer

 

[negitron]

Look at what you put for the radius in your equation.

 

[Bottomsouth]

D = 1.99 x 10^33 / (4/3)(3.14)(7.5 x 10^9)^3 = 2.09 x 10^11?

 

[negitron]

You're off by a factor of 10 somewhere. Careful of your exponents.

 

[Bottomsouth]

D = 1.99 x 10^33 / (4/3)(3.14)(7.5 x 10^8)^3 = 6.338 x 10^23
Seems to be wrong.

 

[negitron]

Your equation is correct. Take it one step at a time.

 

[Redbelly98]

Take it one step at a time.

Agreed. What is the volume? Then take the ratio mass/volume.