# Help, I can't get out!

**Classical Mechanics**Level 3

You stand on a solid sphere of uniform density with total mass \(2 \times 10^{30}~\mbox{kg}\) (the mass of the sun). The escape velocity from the surface of the sphere is equal to the speed of light, \(3 \times 10^8~\mbox{m/s}\). What is the radius of the sphere in **meters**?

**Details and assumptions**

- Newton's constant is \(6.67 \times 10^{-11}~\mbox{Nm}^2/\mbox{kg}^2\).