Question

Calculate work needed to take an iphone 5 from the surface of the Earth to infinity. Google needed constants and parameters.

Answer 1

Work is \[
\int F~dx
\]

Answer 2

We can use \[
F = G\frac{Mm}{x^2}
\]

Answer 3

So I think we will do: \[
W = \int_{x_{\text{Earth radius}}}^{\infty}G\frac{Mm}{x^2}dx
\]

Answer 4

So I think we will do: \[
W = GMm\int_{x_{\text{Earth radius}}}^{\infty}\frac{dx}{x^2}=GMm \left[-\frac{1}{x}\right|_{x_{\text{Earth radius}}}^{\infty} = \frac{GMm}{x_{\text{Earth radius}}}
\]

Answer 5

\(G\) is just a gravitational constant, \(M\) and \(m\) are the masses of Earth and the iPhone 5