A 225 kg red bumper car is moving at 3.0 m/s. It hits a stationary 180 kg blue bumper car. The red and blue bumper cars combine and hit a stationary green bumper car of mass 150 kg. The red, blue, and green bumper cars all combine. What is the final velocity of the combined bumper cars?

Momentum is conserved because the cars combine and move together. The initial momentum is (225 kg)(3.0 m/s) = 675 kg·m/s, and the total mass after all three cars combine is 225 + 180 + 150 = 555 kg. Thus, the final velocity is 675 ÷ 555 ≈ 1.2 m/s, so the correct choice is 1.2 meters per second.

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