Calculate Density of Sphere: Mass, Diameter & Volume

[anoel]

Homework Statement

1.express the volume in terms of the diameter d of the sphere
2.write an equation to find the density of the sphere in terms of mass M and diameter d

Homework Equations

sphere Volume = 4 x pi x r^3 / 3
density = mass/volume

The Attempt at a Solution

1. d=2r so V = d^3 x pi / 6
2. density = M / V(=d^3 x pi /6) = 6M/pi x d^3



but my teacher said it is wrong. what is wrong with my answer?

 

[Filip Larsen]

Assuming you had density written up in your answer like $\frac{6M}{\pi d^3}$ or similar (in the post above you missed some parenthesis) in I don't see anything wrong.