A ball of mass 0.5kg moving at 10ms\(^{-1}\) collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.
A. 0.2ms\(^{-1}\) B. 0.5ms\(^{-1}\) C. 5.0ms\(^{-1}\) D. 5.5ms\(^{-1}\)
