It seems that you've uploaded a file with data regarding the momentum of objects in a collision. To help you solve this problem, we can analyze the given information and the graph to determine the unknown values for mass (m), initial velocities (v_i), and final velocities (v_f).

The table shows some known data:

• For Object b: mass = 3 kg, initial velocity (v_i) = 2 m/s, and the final velocity (v_f) is unknown.
• For Object r: mass is unknown, initial velocity (v_i) = -2 m/s, and final velocity (v_f) is also unknown.

The graph depicts the momentum versus time for both objects. The slope of the momentum vs. time graph can help us calculate the change in momentum, which is related to the impulse and the forces acting on the objects during the collision.

To proceed, we need to:

1. Use the graph to determine the momentum change for both objects.
2. Relate that to the velocity change using the relationship between momentum and velocity:
   $p = mv$
3. Apply the conservation of momentum since the collision is perfectly elastic. The total momentum before the collision must equal the total momentum after the collision.

Would you like to proceed step-by-step with this calculation? Let me know if you need additional explanations or would like me to focus on a specific part of the problem!