At the local radio controlled (RC) airfield, a 2.2 kg RC plane strikes a 1.1 kg aerial drone that is hovering stationary at an altitude of 9.9 m. Just after the collision, the two aircraft are stuck together and moving to the east at 8.1 m/s at an altitude of 9.9 m.
What is the speed (in m/s) of the plane just prior to the collision?