Authorea is an online collaborative writing tool that allows researchers and students to connect with colleagues and co-author classwork, (Einstein 1905) research notes, and papers. Authorea allows users to enrich documents with references, equations, figures, data, source code and comments.

It is well known that \(E=mc^2\), and we can use this to calculate the mass-equivalent of large quantities of energy such as might be contained in an electron accelerated to nearly the speed of light.

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