An object of mass 3.0 kg is projected into the air at an angle of 55 degrees It hits the ground 3.4s later What is the change in momentum while it is in the air?

The initial momentum is 61.0 Newton-seconds at an elevation of 55 degrees to the horizontal while the final momentum has the same magnitude but is at a depression of 55 degrees. This represents a change in momentum of 70 Newton-seconds.