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**1. Homework Statement**

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. Homework 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.

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