## anonymous one year ago q

1. Michele_Laino

here we have to apply the total momentum conservation law

2. Michele_Laino

here is the situation described in your problem: |dw:1437247150772:dw|

3. Michele_Laino

if, after collision the two carts are attached together, then we can write this equation: $\Large 2m{v_0} = \left( {m + 2m} \right)u$ where u is the final velocity

4. Michele_Laino

and v_0=5 m/sec

5. Michele_Laino

so after a simplification, we get: $\Large u = \frac{2}{3}{v_0} = ...?$

6. Michele_Laino

more explanation: the total momentum of our system before collision is: $\Large 2m{v_0}$ whereas the total momentum of our system, after collision is: $\Large \left( {m + 2m} \right)u$ those momentum have to be equal each other

7. Michele_Laino

|dw:1437247606502:dw|

8. Michele_Laino

that's right! u=3.33 m/sec

9. Michele_Laino

where are you confused?

10. Michele_Laino

thanks! :)