Energy, Momentum, and Mass

Students have all heard of E = mc², and many can even say something about what it means. However, few are familiar with the more general form which includes momentum for objects not at rest in a given reference frame. In this activity, we can justify the more complete relationship, E² = p²c² + m²c⁴, and show that when p = 0, the equation reverts to that equation that the whole world knows.