Problem statementSolution video |

**DISCUSSION THREAD**

Any questions??

**Discussion**

**FOUR-STEP PLAN**

* Step 1: FBD* - Draw

*individual*free body diagrams (FBDs) of each particle, along with an FBD of all three particles.

* Step 2: Linear impulse/momentum* - Carefully consider each FBD above. In which directions (if any) is linear momentum conserved for each FBD.

* Step 3: Kinematics* - None needed here.

* Step 4: Solve *- Use the conservation of linear momentum equations from Step 2, along with the coefficient of restitution equation in the "n"-directions for the two impacts.

When finding the direction, do we need the velocity vector, or something else?

Yeah, I was able to find the direction using the velocity vector but I'm sure you could find some other method too.

I just used the velocity vector for direction.

I am confused on how to relate B and C to A. I have linear momentum equations for B and C but they don't have any terms for A.

Treat the collisions between blocks A and C, and A and B separately. You should be able to use the equations we learned in class to find the final velocity of A as a result of each collision separately. Then, add the two results together and determine the final direction of travel.

are we supposed to find the direction of travel using a unit vector or an angle ?

I think you can do whichever you prefer (as long as the angle is marked from a known reference axis, like the x-axis). Since you solved for the velocity of A I think that a unit vector would be easiest.

I'm confused on how to set up the problem. Do you solve for final velocity A first then relate it to C and B in separate vector equations?

As what Joel says above, you need to separate the impacts of spheres B and A and C and A separately. I believe you need to first solve for the final velocities of B and C using the coefficient of restitution linear momentum equations before you can solve for the final velocities of A in their respective positions.