1. The problem statement, all variables and given/known data Near the South Pole, a supply plane going at 120 mph drops a 60 kg supply package into a sled that was initially at rest. After the package lands in the sled, the speed of the sled was found to be 30 m/s. Estimate the mass of the sled. 2. Relevant equations M1V1+M2V2=(M1+M2)V 3. The attempt at a solution Now i know that vertical velocity and horizontal velocity are independent of each other. So it would seem like i just plug, play, and solve for the unknowns. But this seems all too easy, like maybe the vertical motion has an effect on the final velocity. Anyone help?