1. The problem statement, all variables and given/known data The problem states that an object moving at a momentum of 800 m/s( calculated by mass of 80kg x 10 m/s) collides with another object. Both objects are moving forward at 5 m/s. What is the mass of the second object? While moving the objects hit another object moving at 5 m/s in the opposite direction. After the collision they all stop. What is the mass of the 3rd object 2. Relevant equations p=m*v 3. The attempt at a solution For the first part I did Momentum=Mass X Velocity. Since the mass of the first object is known and momentum is conserved I got: p=m*v p=m*5 800=m*5 m= 800/5 m=160kg The mass of the second object is 160kg Now for the 3rd part where they hit an object and stop. The mass of the 3rd object would need to be the same as the combined mass of object 1 and 2. I cannot figure out the equation for this nor do I know if I am on the right track with the solution from part 2. Of course if that is wrong then the entire solution would be wrong. Thank you in advance for any guidance.