1. The problem statement, all variables and given/known data An astronaut is a distance [tex]L[/tex] from her spaceship, and is at rest with respect to the ship, when she discovers that her tether has broken. She tosses a wrench with a speed of [tex]V_W[/tex] in the opposite direction of the ship to propel herself back to the ship. The astronaut has mass [tex]M_A[/tex], and the wrench has mass [tex]M_W[/tex]. How long does it take her to reach the ship in terms of [tex]L[/tex], [tex]M_A[/tex], [tex]M_W[/tex] and [tex]V_W[/tex]? 2. Relevant equations Conservation of momentum: [tex]P_i=P_f[/tex] I don't know what equation to use to find time? [tex]v= d/t[/tex]? 3. The attempt at a solution [tex](M_A+M_W)(V_i)=(M_W)(V_Wf)-(M_A)(V_Af)[/tex] [tex]V_Af=(M_f)(V_Wf)/(M_A)[/tex] [tex]t=d/v[/tex] [tex]t=(L)(M_A)/(M_W)(V_Wf)[/tex] Is that right? Thanks.